The results of this study are surprising. In those with schizophrenia, those on clozapine had by far the lowest relative risk of death (compared to patients on other antipsychotics). Compared to older medications, atypical antipsychotics, to date, do not seem to be impacting on the relative risk of death.

I congratulate the authors on this impressive study. The study is another reminder of the utility of population-based record linkage studies. Thank heavens for the Nordic countries' health registers.

A few years ago we wondered if the differential mortality rate for schizophrenia was worsening over time (Saha et al., 2007). In addition to differential access to health care, we worried that the adverse effects of atypical antipsychotics might be a “ticking time bomb” for worsening mortality in the decades to come. The new Finnish study shows a more nuanced picture emerging.

While the results are thought provoking, let’s not forget about the main game. We all agree that there is still much more work to be done in...  Read more

The results of this study are surprising. In those with schizophrenia, those on clozapine had by far the lowest relative risk of death (compared to patients on other antipsychotics). Compared to older medications, atypical antipsychotics, to date, do not seem to be impacting on the relative risk of death.

I congratulate the authors on this impressive study. The study is another reminder of the utility of population-based record linkage studies. Thank heavens for the Nordic countries' health registers.

A few years ago we wondered if the differential mortality rate for schizophrenia was worsening over time (Saha et al., 2007). In addition to differential access to health care, we worried that the adverse effects of atypical antipsychotics might be a “ticking time bomb” for worsening mortality in the decades to come. The new Finnish study shows a more nuanced picture emerging.

While the results are thought provoking, let’s not forget about the main game. We all agree that there is still much more work to be done in optimizing the general physical health of people with schizophrenia.

References:

Saha S, Chant D, McGrath J. A systematic review of mortality in schizophrenia: is the differential mortality gap worsening over time? Arch Gen Psychiatry . 2007 Oct 1 ; 64(10):1123-31. Abstract

Clozapine: A First-Line Antipsychotic?
Tiihonen et al., of the University of Kuopio in Finland, compared mortality rates in over 66,000 patients with schizophrenia with the entire population of Finland and concluded that clozapine should be used as a first-line drug in the treatment of this disorder. Clozapine is a very effective antipsychotic, and for patients who have received it for several years, the improvement in clinical status can be quite remarkable (Lindstrom, 1988; Agid et al., 2008). Additionally, the improved mortality rate of patients on clozapine may be attributable, at least in part, to the close monitoring of their white blood cell count (WBC).

The stipulation that weekly or biweekly blood samples must be drawn is not an issue that can be viewed lightly, because approximately 1-2 percent of patients on clozapine may show significant decreases in their WBC. This may be a harbinger of agranulocytosis, a potentially lethal form of morbidity in which the...  Read more

Clozapine: A First-Line Antipsychotic?
Tiihonen et al., of the University of Kuopio in Finland, compared mortality rates in over 66,000 patients with schizophrenia with the entire population of Finland and concluded that clozapine should be used as a first-line drug in the treatment of this disorder. Clozapine is a very effective antipsychotic, and for patients who have received it for several years, the improvement in clinical status can be quite remarkable (Lindstrom, 1988; Agid et al., 2008). Additionally, the improved mortality rate of patients on clozapine may be attributable, at least in part, to the close monitoring of their white blood cell count (WBC).

The stipulation that weekly or biweekly blood samples must be drawn is not an issue that can be viewed lightly, because approximately 1-2 percent of patients on clozapine may show significant decreases in their WBC. This may be a harbinger of agranulocytosis, a potentially lethal form of morbidity in which the bone marrow loses its ability to generate leukocytes; death remains a significant risk for patients taking this drug (Taylor et al., 2009). To some, this may seem like a small price to pay for an improved quality of life. For others, however, it represents an unacceptable degree of risk. Additionally, many patients consider the requirement for frequent blood drawing as intrusive and/or painful and refuse to have it done (personal observation).

Perhaps the greatest source of resistance to using clozapine as a “first-line” drug is the psychiatrist who is faced with this decision. In general, most believe that they would be exposing their patient to unnecessary risk and prefer to look toward other, more “benign” antipsychotic drugs (APDs) for treatment options. In practice, however, the second-generation atypical APDs are not necessarily better candidates for “first-line” use, because they may be even more likely to cause excessive weight gain, diabetes mellitus, and cardiovascular disease (Wehring et al., 2003; Henderson et al., 2005) and result in increased mortality (Meatherall and Younes, 2002). In addition to the risk of agranulocytosis, clozapine may also cause unacceptable amounts of sedation, drooling, and weight gain. Typical APDs, on the other hand, are associated with other side effects that can be quite debilitating. These include extrapyramidal movement disorders, such as 1) akathisia, a condition that may cause a worsening of symptoms as a result of agitation; 2) drug-induced Parkinsonism, in which hypokinesia usually complicates the negative symptoms of schizophrenia; and 3) tardive dyskinesia, a syndrome in which there are involuntary movements of the tongue and lips that can result in significant disability and even disfigurement (Peacock et al., 1996).

In considering the choice of an APD for a “first-episode” patient with schizophrenia, all of these factors must be considered. It is impossible to know how a particular patient with no prior history of having taken an APD will respond to any given drug. What may be an excellent “first-line” drug for one patient may not be so for another. So, the choice of a “first-line” drug requires that the doctor and patient work together to identify the APD that is most appropriate at a particular time in the course of the illness, particularly if the patient has a treatment-sensitive or treatment-resistant form of schizophrenia (Wang et al., 2004).

References:

Agid O, Kapur S, Remington G. Emerging drugs for schizophrenia. Expert Opin Emerg Drugs. 2008;13:479-95. Abstract

Henderson DC, Nguyen DD, Copeland PM, Hayden DL, Borba CP, Louie PM, Freudenreich O, Evins AE, Cather C, Goff DC. Clozapine, diabetes mellitus, hyperlipidemia, and cardiovascular risks and mortality: results of a 10-year naturalistic study. J Clin Psychiatry. 2005;66:1116-21. Abstract

Lindstrom LH. The effect of long-term treatment with clozapine in schizophrenia: a retrospective study in 96 patients treated with clozapine for up to 13 years. Acta Psychiatr Scand. 1988;77:524-9. Abstract

Meatherall R, Younes J. Fatality from olanzapine induced hyperglycemia. J Forensic Sci. 2002;47:893-6. Abstract

Peacock L, Solgaard T, Lublin H, Gerlach J . Clozapine versus typical antipsychotics. A retro- and prospective study of extrapyramidal side effects. Psychopharmacology (Berl). 1996; 124:188-96. Abstract

Taylor DM, Douglas-Hall P, Olofinjana B, Whiskey E, Thomas A. Reasons for discontinuing clozapine: matched, case-control comparison with risperidone long-acting injection. Br J Psychiatry. 2009;194:165-7. Abstract

Wang PS, Ganz DA, Benner JS, Glynn RJ, Avorn J. Should clozapine continue to be restricted to third-line status for schizophrenia?: a decision-analytic model. J Ment Health Policy Econ. 2004;7:77-85. Abstract

Wehring HJ, Kelly DL, Love RC, Conley RR. Deaths from diabetic ketoacidosis after long-term clozapine treatment. Am J Psychiatry. 2003;160:2241-2. Abstract

Dr. Benes notes that clozapine is "...a very effective antipsychotic, and...improvement in clinical status can be quite remarkable." The mortality figures reported by Tihonen et al. have proved quite striking to schizophrenia researchers. The perception within the psychiatry community that clozapine is too risky for first-line therapy needs further assessment and discussion. Only about 5 percent of schizophrenics in the U.S. receive clozapine (Lieberman, 2009), leaving the vast majority of patients undermedicated because of this perception. The major issue with starting a patient on clozapine is WBC monitoring. I would like to call upon the NIMH to establish a major study in which schizophrenics are introduced to clozapine on an inpatient basis for 30-60 days to establish safety. It is well known that most WBC events associated with clozapine occur in the first few weeks of treatment. Also, I note that current prescribing practice with clozapine actually allows for monthly blood monitoring after 12 months of continuous clozapine use. Thus, the burden of monitoring diminishes...  Read more

Dr. Benes notes that clozapine is "...a very effective antipsychotic, and...improvement in clinical status can be quite remarkable." The mortality figures reported by Tihonen et al. have proved quite striking to schizophrenia researchers. The perception within the psychiatry community that clozapine is too risky for first-line therapy needs further assessment and discussion. Only about 5 percent of schizophrenics in the U.S. receive clozapine (Lieberman, 2009), leaving the vast majority of patients undermedicated because of this perception. The major issue with starting a patient on clozapine is WBC monitoring. I would like to call upon the NIMH to establish a major study in which schizophrenics are introduced to clozapine on an inpatient basis for 30-60 days to establish safety. It is well known that most WBC events associated with clozapine occur in the first few weeks of treatment. Also, I note that current prescribing practice with clozapine actually allows for monthly blood monitoring after 12 months of continuous clozapine use. Thus, the burden of monitoring diminishes sharply after one year.

References:

Lieberman J. A Beacon of Hope: Prospects for Preventing and Recovering from Mental Illness. NARSAD Research Quarterly 2 (1), Winter 2009.

The Lieberman et al. CATIE study is a landmark large-scale clinical trial of antipsychotic drug therapy and will generate considerable discussion in the coming months. It offers important insights about real-world treatment of individuals with the diagnosis of schizophrenia, in the sense of typical practices in clinics around the country and the clinical experience of many practitioners. It probably comes as no surprise that the response to available antipsychotic agents is suboptimal and that differences between drugs are not dramatic in many cases.

One of the questions that comes to my mind about the results is whether and to what degree they are generalizable. Do the results of this study accurately characterize the effects of these drugs across the spectrum of patients with chronic schizophrenia who are treated with them? In other words, are the patients in the CATIE trial representative of the patients with chronic schizophrenia who are in need of these medications? I believe there are several indicators to suggest that they may not be. First, of the subjects in this...  Read more

The Lieberman et al. CATIE study is a landmark large-scale clinical trial of antipsychotic drug therapy and will generate considerable discussion in the coming months. It offers important insights about real-world treatment of individuals with the diagnosis of schizophrenia, in the sense of typical practices in clinics around the country and the clinical experience of many practitioners. It probably comes as no surprise that the response to available antipsychotic agents is suboptimal and that differences between drugs are not dramatic in many cases.

One of the questions that comes to my mind about the results is whether and to what degree they are generalizable. Do the results of this study accurately characterize the effects of these drugs across the spectrum of patients with chronic schizophrenia who are treated with them? In other words, are the patients in the CATIE trial representative of the patients with chronic schizophrenia who are in need of these medications? I believe there are several indicators to suggest that they may not be. First, of the subjects in this trial, most of whom (75 percent) were male, 40 percent had been or were married. Second, the mean age at first antipsychotic treatment was 26 years. Third, 30 percent of the subjects were on no medication when they entered the trial. These are all somewhat atypical characteristics in my experience, especially for a predominantly male sample.

In the NIMH schizophrenia genetic study that I direct, we have extensively evaluated over 600 subjects with schizophrenia from around the country. In our sample, the mean age at first antipsychotic treatment is 21 and the ever-married rate is 15 percent, and our sample is one-third female. Moreover, less than 10 percent of our sample is unmedicated at the time that they are evaluated. The finding that a mean dose of 20 mg of perphenazine was as effective as other medications also is somewhat surprising in my experience, as having used this drug for many years, I have rarely seen chronic, actively symptomatic patients respond well without dosing around 32 milligrams and above. Is it possible that the CATIE trial inadvertently enrolled patients more in the schizophrenia spectrum end of the distribution of patients receiving these drugs who may tend not to show as clear benefit? Or maybe the size and breadth of the CATIE trial obscured the signal from the more classic patient with schizophrenia for whom antipsychotic treatment is essential.

It will be interesting to see whether other academic schizophrenia centers concur with the demographics of my experience as noted above or those of CATIE. Multicenter studies—and CATIE involved 57 centers each contributing relatively small samples over a 2-year period—are susceptible to dilution effects and to the possibility that the sample is clinically "noisy." It will be interesting to see, when data analyses from the next stages appear, whether differences are found in the results from different centers who participated in the trial. Will CATIE have told the story of how these drugs work in patients who receive them, or will it have failed to identify the signal from the noise?

I also have not seen the response at that dose of perphenazine and even the atypical antipsychotics in chronic schizophrenics. In fact, the only medication that seemed to have an adequate "real-life" dose was olanzapine.

View all comments by Max Schubert

It seems that the doses used are not equivalent, and the researchers have used somewhat lower doses of perphenazine and risperidone (in favor of olanzapine). Thus, it is obvious that perphenazine and risperidone have showed smaller efficacy.

View all comments by Iulian Iancu

There is evidence that the Chinese traditional medicines may be an alternative approach in the treatment of schizophrenia. Our recent studies indicate that the extraction of gingko biloba may increase the effectiveness of antipsychotic drugs, but reduce their side effects. This finding may provide a new clue to develop a novel therapeutic drug for treatment of schizophrenia.

References:
1. Zhang XY, Zhou DF, Zhang PY, Wu GY, Su JM, Cao LY. A double-blind, placebo-controlled trial of extract of Ginkgo biloba added to haloperidol in treatment-resistant patients with schizophrenia. Journal of Clinical Psychiatry. 2001; 62(11):878-83. Abstract

2. Zhang XY, Zhou DF, Su JM, Zhang PY. The effect of extract of ginkgo biloba added to haloperidol on superoxide dismutase in inpatients with chronic schizophrenia. Journal of Clinical Psychopharmacology 2001;21(1):85-88. Abstract

View all comments by Xiang Zhang

Reply to Dr. Weinberger's questions about the generalizability of the CATIE sample, by Marvin Swartz, for the CATIE investigators
As CATIE investigators, we have been mindful of concerns about the generalizability of the CATIE sample. In response to a similar concern, our colleague Jeffrey Swanson at Duke compared CATIE participants to a quasi-random sample of 1,413 patients enrolled in the Schizophrenia Care and Assessment Program (SCAP), an observational, non-interventional study of schizophrenia treatment in usual care settings in the United States. The two samples were similar in demographic characteristics, e.g., gender (70 percent male in SCAP, 74 percent male in CATIE), age (mean age = 43 years in SCAP, mean age = 41 years in CATIE), and education (36 percent of SCAP participants had a high school education and 28 percent attended college; in CATIE these percentages were 35 percent and 39 percent, respectively). The CATIE study had a lower proportion of participants from racial minority backgrounds (40 percent vs. 54 percent). The samples also resembled...  Read more

Reply to Dr. Weinberger's questions about the generalizability of the CATIE sample, by Marvin Swartz, for the CATIE investigators
As CATIE investigators, we have been mindful of concerns about the generalizability of the CATIE sample. In response to a similar concern, our colleague Jeffrey Swanson at Duke compared CATIE participants to a quasi-random sample of 1,413 patients enrolled in the Schizophrenia Care and Assessment Program (SCAP), an observational, non-interventional study of schizophrenia treatment in usual care settings in the United States. The two samples were similar in demographic characteristics, e.g., gender (70 percent male in SCAP, 74 percent male in CATIE), age (mean age = 43 years in SCAP, mean age = 41 years in CATIE), and education (36 percent of SCAP participants had a high school education and 28 percent attended college; in CATIE these percentages were 35 percent and 39 percent, respectively). The CATIE study had a lower proportion of participants from racial minority backgrounds (40 percent vs. 54 percent). The samples also resembled each other in clinical characteristics. Nearly one-third of the patients in both studies had recently been hospitalized. The CATIE sample had slightly higher average scores on psychotic symptom severity than the SCAP patients (mean PANSS total score = 75 vs. 71), and also slightly higher scores on functioning and quality of life (mean Heinrichs-Carpenter QLS score = 63 vs. 57) (Haya Ascher-Svanum, Ph.D., Senior Research Scientist, Eli Lilly and Company; personal communication). These similarities provide some confidence that CATIE’s RCT design did not result in a biased selection of patients.

Thanks for your comments on the CATIE study.

The antipsychotic drugs mainly treat psychosis (in contrast to cognition impairments and primary negative symptoms). In the CATIE study, the drugs tested share the same mechanism of action (D2 antagonism). Clozapine aside, the second-generation drugs (SGA) have not established superior efficacy over first-generation drugs (FGA). The FDA has granted no such claim, and the Cochrane reviews do not support superior antipsychotic efficacy. The appearance of superiority, including the terrific organization of data in the Davis meta-analyses, may be extensively based on last observation carried forward, excessive dose of the FGA, failure to pretreat with anti-parkinsonian drugs, sponsor bias, and a number of other methodological problems including the fact that most study subjects are doing poorly on FGA when recruited into comparative studies. "Atypical antipsychotic" means only low extrapyramidal symptoms at therapeutic dosing. In this regard, the CATIE findings are not surprising, but simply point to the considerable shortfall in effectiveness associated with current treatments....  Read more

The antipsychotic drugs mainly treat psychosis (in contrast to cognition impairments and primary negative symptoms). In the CATIE study, the drugs tested share the same mechanism of action (D2 antagonism). Clozapine aside, the second-generation drugs (SGA) have not established superior efficacy over first-generation drugs (FGA). The FDA has granted no such claim, and the Cochrane reviews do not support superior antipsychotic efficacy. The appearance of superiority, including the terrific organization of data in the Davis meta-analyses, may be extensively based on last observation carried forward, excessive dose of the FGA, failure to pretreat with anti-parkinsonian drugs, sponsor bias, and a number of other methodological problems including the fact that most study subjects are doing poorly on FGA when recruited into comparative studies. "Atypical antipsychotic" means only low extrapyramidal symptoms at therapeutic dosing. In this regard, the CATIE findings are not surprising, but simply point to the considerable shortfall in effectiveness associated with current treatments. The drugs will vary considerably along side effect liabilities, and matching patient to side effect profile is the key to individualizing drug choice at the moment.

As to time on drug, there was not a long-acting depot arm to the study, and this method should probably be considered in substantially more patients than is the practice in the U.S. Olanzapine did a little better on the time on drug measure, and risperidone was second. This may relate to the fact that these were the two most common drugs used at study onset, so more patients with known tolerability to these drugs began the trial. In any case, concern with weight and the metabolic syndrome will drastically cut the time on drug for olanzapine in current practice.

It is almost impossible to have a level playing field in comparative drug studies, since optimal dosing and individualized dosing parameters are simply little known with most antipsychotic drugs. In this regard, we don't know if quetiapine and ziprasidone would have done better at higher dose; or if risperidone being yoked to olanzapine led to suboptimal dosing in many cases. In Rosenheck's JAMA report, he observed that pretreatment with an anti-parkinsonian drug led to similar effectiveness comparing olanzapine with haloperidol. Would perphenazine have been even better with anti-cholinergic pretreatment?

In my view, this is a critically important study in that it reasonably represents an effectiveness study in typical settings [probably more representative than the Weinberger data set (see Weinberger commentary)] without sponsor bias. As such, it has succeeded in calling public attention to the relative lack of progress associated with "me-too" dopamine blocking antipsychotic drugs. This conclusion is reinforced by the U.K. study reported by Peter Jones at the ICOSR where SGA did not beat FGA on the primary endpoint (quality of life) or on many secondary measures. Another head-on comparison study with public support.

My hope is that industry will devote discovery resources to the challenging problems of novel treatments with new molecular targets addressing problems with impaired cognition and primary negative psychopathology. Refining antipsychotic drugs has not advanced therapeutics much since the introduction of chlorpromazine. Reducing the neuroleptic adverse effects of FGA is a real advance, especially considering the excessive dosing. But significant new liabilities are associated with some of the SGA. We now need to meet the efficacy challenge for the components of schizophrenia that mainly cause poor functional outcomes.

Dr. Swarz's comment providing data from the SCAP study is helpful in confirming that CATIE patients are similar in many phenomenological respects to other patients in schizophrenia treatment programs. Indeed, in terms of PANSS ratings, sex ratios, age at enrollment in the study, and history of recent hospitalizations, CATIE patients are not substantially different from patients we see at the NIH in Bethesda, Maryland and we saw when our program was located at St. Elizabeths Hospital in Washington, D.C. In my comment, I asked specifically about three CATIE characteristics that seemed atypical to me: age at first antipsychotic treatment (26), precentage of patients who were or had been married (40%), and percentage of patients who were unmedicated at the time they volunteered for the study (30%). It would enlighten this discussion if Dr. Swarz would report these data from the SCAP study.

View all comments by Daniel Weinberger

It would be interesting to learn from Dr. Swartz and the CATIE investigators (a) the age at first antipsychotic treatment, (b) the percentage of patients who were or had been married, and (c) the percentage of patients who were unmedicated at the time they volunteered for the study in the SCAP sample. I suspect these three variables, if available, will more closely resemble those of the CATIE trial sample than the CBDB sibling study sample.

Dr. Weinberger has suggested that the CATIE trial inadvertently enrolled patients more in the schizophrenia spectrum end of the distribution, or maybe the size and breadth of the CATIE trial obscured the signal from the more classic patient with schizophrenia, so the results may not be generalizable. I suspect that differences in criteria for recruitment and retention between the CBDB sibling study and the CATIE study explain the differences among the demographic variables of the samples.

The clinical characteristics of the CBDB sibling study sample are what one would expect in a study whose purpose is to find associations between...  Read more

It would be interesting to learn from Dr. Swartz and the CATIE investigators (a) the age at first antipsychotic treatment, (b) the percentage of patients who were or had been married, and (c) the percentage of patients who were unmedicated at the time they volunteered for the study in the SCAP sample. I suspect these three variables, if available, will more closely resemble those of the CATIE trial sample than the CBDB sibling study sample.

Dr. Weinberger has suggested that the CATIE trial inadvertently enrolled patients more in the schizophrenia spectrum end of the distribution, or maybe the size and breadth of the CATIE trial obscured the signal from the more classic patient with schizophrenia, so the results may not be generalizable. I suspect that differences in criteria for recruitment and retention between the CBDB sibling study and the CATIE study explain the differences among the demographic variables of the samples.

The clinical characteristics of the CBDB sibling study sample are what one would expect in a study whose purpose is to find associations between genetic variation and neuroimaging/neuropsychological phenotypes, among affected and unaffected family members. The usual patient included in the CBDB sample probably: had onset of active symptoms in late adolescence or early adulthood (i.e., high school or college age, before many people marry); was started on medications earlier in life; and had more intact nuclear families (parents, siblings, etc.) than the usual CATIE subject. Patients with later onset of illness or milder symptoms (who are more likely to be or have been married) and who did not start on medications once psychotic symptoms occurred, were less compliant with their medications, and/or had fewer intact family relationships were unlikely to successfully travel to Bethesda and complete two full days of research testing. The CATIE recruitment strategy did not exclude the unusual patient with treatment of symptoms later in adulthood, require intact nuclear family, or require compliance with medications at time of study entry.

The CBDB sample better represents a "textbook case" of schizophrenia. Many patients who do meet DSM-IV criteria for schizophrenia may not be good candidates for a genetics study, but may still have schizophrenia and are appropriate candidates for a large clinical study. This would suggest that the findings can be generalized to other groups of patients with the illness, though perhaps not the "classic" cases of schizophrenia gathered in the CBDB study.

Is there any published evidence that gingko biloba could be useful in containing the side effects of clozapine and other atypicals, or are there studies in progress?

View all comments by Captain Johann Samuhanand

Reply to comment by Johann Samuhanand
To our best knowledge, there is no published evidence that gingko biloba could be useful in reducing the side effects of clozapine and other atypicals. However, using the same group of patients with schizophrenia as we reported previously (Zhang et al., 2001), our recent study has shown that chronic patients with schizophrenia demonstrated significantly lower CD3+, CD4+, and IL-2 secreting cells, together with CD4/CD8 ratio, than did healthy controls at baseline. After a 12-week treatment, EGb added to haloperidol treatment increased the initially low peripheral CD3+, CD4+, and IL-2 secreting cells, together with CD4/CD8 ratio. There was only a significant increase in CD4+ cells in the placebo plus haloperidol group. These findings suggest that ginkgo biloba may improve the decreased peripheral immune functions in schizophrenia (Zhang et al., 2006).

As we have known, although clozapine is superior over the other drugs in terms of efficacy,...  Read more

Reply to comment by Johann Samuhanand
To our best knowledge, there is no published evidence that gingko biloba could be useful in reducing the side effects of clozapine and other atypicals. However, using the same group of patients with schizophrenia as we reported previously (Zhang et al., 2001), our recent study has shown that chronic patients with schizophrenia demonstrated significantly lower CD3+, CD4+, and IL-2 secreting cells, together with CD4/CD8 ratio, than did healthy controls at baseline. After a 12-week treatment, EGb added to haloperidol treatment increased the initially low peripheral CD3+, CD4+, and IL-2 secreting cells, together with CD4/CD8 ratio. There was only a significant increase in CD4+ cells in the placebo plus haloperidol group. These findings suggest that ginkgo biloba may improve the decreased peripheral immune functions in schizophrenia (Zhang et al., 2006).

As we have known, although clozapine is superior over the other drugs in terms of efficacy, it can severely deplete white blood cells, leading to limitations on its use. If gingko biloba may indeed produce beneficial effects on the immune system in schizophrenia, there is a possibility that ginkgo biloba may be useful in reducing the side effects of clozapine, at least in regard to immune function.

On the other hand, a limitation of the design of our previous study (Zhang et al., 2001) is the use of haloperidol as the antipsychotic treatment at a time when atypical antipsychotic drugs are the standard of care. Therefore, a further study is warranted to investigate whether ginkgo biloba shows similar benefits in augmenting the atypical antipsychotics, which already have the capacity to improve the positive and negative symptoms and have better profiles in terms of extrapyramidal side effects.

References:
Zhang XY, Zhou DF, Zhang PY, Wu GY, Su JM, Cao LY. A double-blind, placebo-controlled trial of extract of Ginkgo biloba added to haloperidol in treatment-resistant patients with schizophrenia. Journal of Clinical Psychiatry. 2001; 62(11):878-83. Abstract

Zhang XY, Zhou DF, Cao LY, Wu GY. The effects of Ginkgo biloba extract added to haloperidol on peripheral T-cell subsets in drug-free schizophrenia: a double-blind, placebo-controlled trial. Psychopharmacology 2006 (in press)

I recommend this clear and well-written paper for students to understand the basis of the CATIE studies.

I agree with Dr. Weinberger about the variables that could obscure the results in the target population or the schizophrenic population. His remarks about the control conditions or the dissection of the variables in the study are important. The difference between typical and atypical drugs is clear in these data.

New drugs, diferent from the typical and atypical drugs, based on new genetics research and new genetic routes must be developed in order to achieve new successes in the treatment of schizophrenia.

I think that atypical antipsychotics do not mean only low extrapyramidal symptoms at therapeutic doses. Several studies have demonstrated that atypical drugs(especially olanzapine) are better than typical drugs in important characteristics such as cognitive functioning.

View all comments by Patricia Estani

The most important current development of new antipsychotic drugs is focused on two mechanisms, the α7-nicotinic receptor agonists that are good new candidates for the management of the disease (Martin et al., 2004) and, most recently (and I think probably the closest to development), is the one that focuses on glutamatergic neurotransmission (Coyle and Tsai, 2004).

On the other hand, I think that behavioral and cognitive therapy, as well as family support and family management given by a professional in this area of health, are important to ensure an excellent result in schizophrenic patients.

References:
Martin LF, Kem WR, Freedman R. Alpha-7 nicotinic receptor agonists: potential new candidates for the treatment of schizophrenia. Psychopharmacology (Berl). 2004 Jun ;174(1):54-64. Abstract

Coyle JT, Tsai G. The NMDA receptor glycine modulatory site: a therapeutic target for improving cognition and reducing negative symptoms in schizophrenia. Psychopharmacology (Berl). 2004 Jun ;174(1):32-8. Abstract

View all comments by Patricia Estani

[Disclosure: R. Fisher was Study Coordinator, Recruiter, and Diagnostician for the Byerly Group at UT Southwestern CATIE site, the second-largest enrollment site in the study.]

The CATIE study is likely the best designed and implemented research project ever conducted regarding schizophrenia and relevant psychopharmacology. The extensively collected data will have an enormous heuristic value in the study and evaluation of this disorder in all aspects of schizophreinia. I found Drs. Lieberman and McEvoy to be true professionals in this study design.

View all comments by Robert Fisher

These are solid studies. I wonder, though, how many of these patients are on statins to prevent atherosclerosis? Is there evidence that people with schizophrenia at risk of atherosclerosis (perhaps most of them?) are routinely given proper cardiovascular medicine?

View all comments by Steven Erickson

Atmaca and colleagues report that atypical antipsychotic-, especially clozapine- and olanzapine-induced weight gain is related to increased levels of leptin. How does this tie in with the study by Sangwon Kim and colleagues, who found that clozapine and olanzapine lower levels of active AMPK in mouse hypothalamus tissue while leptin activates hypothalamic AMPK?

Wannamethee et al. conclude, "Plasma leptin is associated with insulin resistance, inflammation, and disturbances in homeostasis independent of waist circumference, suggesting possible pathways by which leptin may influence risk of cardiovascular disease." They also report that leptin is lowered in cigarette smokers.

It is of interest that De Rosa and colleagues report reduced activation of FOXP3 by leptin. Is this a positive or a negative in schizophrenia? Is there a...  Read more

Atmaca and colleagues report that atypical antipsychotic-, especially clozapine- and olanzapine-induced weight gain is related to increased levels of leptin. How does this tie in with the study by Sangwon Kim and colleagues, who found that clozapine and olanzapine lower levels of active AMPK in mouse hypothalamus tissue while leptin activates hypothalamic AMPK?

Wannamethee et al. conclude, "Plasma leptin is associated with insulin resistance, inflammation, and disturbances in homeostasis independent of waist circumference, suggesting possible pathways by which leptin may influence risk of cardiovascular disease." They also report that leptin is lowered in cigarette smokers.

It is of interest that De Rosa and colleagues report reduced activation of FOXP3 by leptin. Is this a positive or a negative in schizophrenia? Is there a predisposition to develop autoimmune disease with long-term use of these drugs?

The article by Kargieman and colleagues further specifies the cellular mechanisms underlying the actions of clozapine in a model of pharmacologically induced cortical dysfunction. Separately, clozapine has been demonstrated to be capable of reducing or eliminating the complex behavioral and cognitive impairments elicited by acutely administered NMDA antagonists (Geyer et al., 2001; Idris et al., 2005; Lipina et al., 2005), and these cellular mechanisms shown by Kargieman et al. may represent the level of interaction between clozapine and phencyclidine-like drugs.

What is surprising from so many of these studies is the quality of the reversal of effects produced by clozapine, despite the fact that it (like most other antipsychotic drugs) has limited efficacy both at an individual and population level. Furthermore, there remain many reports in the literature demonstrating that while some cognitive and symptomatic domains in schizophrenia...  Read more

The article by Kargieman and colleagues further specifies the cellular mechanisms underlying the actions of clozapine in a model of pharmacologically induced cortical dysfunction. Separately, clozapine has been demonstrated to be capable of reducing or eliminating the complex behavioral and cognitive impairments elicited by acutely administered NMDA antagonists (Geyer et al., 2001; Idris et al., 2005; Lipina et al., 2005), and these cellular mechanisms shown by Kargieman et al. may represent the level of interaction between clozapine and phencyclidine-like drugs.

What is surprising from so many of these studies is the quality of the reversal of effects produced by clozapine, despite the fact that it (like most other antipsychotic drugs) has limited efficacy both at an individual and population level. Furthermore, there remain many reports in the literature demonstrating that while some cognitive and symptomatic domains in schizophrenia are improved by clozapine, others clearly are not (Goldberg and Weinberger, 1996; Bilder et al., 2002). Why, then, is clozapine so effective in the PCP model? One concern, of course, is that its effects are related to a specific type of pharmacological interaction; one certainly needs to see clozapine's effects in other models that do not involve the acute administration of an NMDA antagonist.

Notably, several groups have been studying the effects of long-term administration of phencyclidine, sometimes followed by washout of the NMDA antagonist, to develop an alternative type of model that may depend upon the neuroadaptations resulting from blockade of NMDA receptors, rather than on the acute pharmacological action itself (Jentsch et al., 1997; Balla et al., 2003; Amitai et al., 2007, and many others). Whilst the specific validity of any one of these approaches is debatable, what appears to be clear is that the ability of clozapine to reverse behavioral or neurochemical deficits is much more tenuous. Is this a weakness of these models, or does it mean they are actually more realistic in their predictions?

Based upon these facts, one is left with a number of questions. First, is a model that predicts that clozapine is completely effective at blocking psychopathology or pathophysiology valid? Second, is the action of clozapine in any one model based upon one kind of manipulation really that provocative? And finally (and perhaps most importantly), is developing models that explain how clozapine works really in our best interest, or is it time to move beyond models that predict marginal gains from existing drugs, in order to look to targets flowing from the new valid genetic mechanisms that appear to hold the keys to the next generation of treatments for schizophrenia?

References:

Amitai N, Semenova S, Markou A. Cognitive-disruptive effects of the psychotomimetic phencyclidine and attenuation by atypical antipsychotic medications in rats. Psychopharmacology (Berl). 2007 Sep;193(4):521-37. Abstract

Balla A, Sershen H, Serra M, Koneru R, Javitt DC. Subchronic continuous phencyclidine administration potentiates amphetamine-induced frontal cortex dopamine release. Neuropsychopharmacology. 2003 Jan;28(1):34-44. Abstract

Bilder RM, Goldman RS, Volavka J, Czobor P, Hoptman M, Sheitman B, Lindenmayer JP, Citrome L, McEvoy J, Kunz M, Chakos M, Cooper TB, Horowitz TL, Lieberman JA. Neurocognitive effects of clozapine, olanzapine, risperidone, and haloperidol in patients with chronic schizophrenia or schizoaffective disorder. Am J Psychiatry. 2002 Jun;159(6):1018-28. Abstract

Geyer MA, Krebs-Thomson K, Braff DL, Swerdlow NR. Pharmacological studies of prepulse inhibition models of sensorimotor gating deficits in schizophrenia: a decade in review. Psychopharmacology (Berl). 2001 Jul;156(2-3):117-54. Abstract

Goldberg TE, Weinberger DR. Effects of neuroleptic medications on the cognition of patients with schizophrenia: a review of recent studies. J Clin Psychiatry. 1996;57 Suppl 9:62-5. Abstract

Idris NF, Repeto P, Neill JC, Large CH. Investigation of the effects of lamotrigine and clozapine in improving reversal-learning impairments induced by acute phencyclidine and D-amphetamine in the rat. Psychopharmacology (Berl). 2005 May;179(2):336-48. Abstract

Jentsch JD, Redmond DE Jr, Elsworth JD, Taylor JR, Youngren KD, Roth RH. Enduring cognitive deficits and cortical dopamine dysfunction in monkeys after long-term administration of phencyclidine. Science. 1997 Aug 15;277(5328):953-5. Abstract

Lipina T, Labrie V, Weiner I, Roder J. Modulators of the glycine site on NMDA receptors, D-serine and ALX 5407, display similar beneficial effects to clozapine in mouse models of schizophrenia. Psychopharmacology (Berl). 2005 Apr;179(1):54-67. Abstract

The paper by Kargieman et al. provides an interesting perspective on the effects of PCP on activity in the prefrontal cortex. Dr. Javitt brings up an excellent point in his commentary that the study highlights the importance of PCP in this preparation as a model of slow-wave sleep disturbances in schizophrenia. In anesthetized animals, field potential recordings resemble the up and down states observed in slow-wave sleep. These states are driven by NMDA receptors and, accordingly, NMDA antagonists such as PCP and ketamine should reduce them as reported. The odd thing about NMDA antagonists is that they themselves can be used as anesthetics to produce a state where slow delta oscillations predominate. For instance, robust up and down states or slow oscillations at or below delta are observed when ketamine is used as an anesthetic. Therefore, NMDA antagonists can induce a state where delta activity is prominent, yet if the subject is already in that state, the effect of the drug is to reduce such activity.

So this also may be the case with PCP. There are numerous EEG studies...  Read more

The paper by Kargieman et al. provides an interesting perspective on the effects of PCP on activity in the prefrontal cortex. Dr. Javitt brings up an excellent point in his commentary that the study highlights the importance of PCP in this preparation as a model of slow-wave sleep disturbances in schizophrenia. In anesthetized animals, field potential recordings resemble the up and down states observed in slow-wave sleep. These states are driven by NMDA receptors and, accordingly, NMDA antagonists such as PCP and ketamine should reduce them as reported. The odd thing about NMDA antagonists is that they themselves can be used as anesthetics to produce a state where slow delta oscillations predominate. For instance, robust up and down states or slow oscillations at or below delta are observed when ketamine is used as an anesthetic. Therefore, NMDA antagonists can induce a state where delta activity is prominent, yet if the subject is already in that state, the effect of the drug is to reduce such activity.

So this also may be the case with PCP. There are numerous EEG studies showing that PCP significantly increases activity in the delta band of awake humans or animals (Stockard et al., 1976; Matsuzaki and Dowling, 1985; Mattia et al.,1988; Marquis et al., 1989; Yamamoto, 1997; Sebban et al., 2002), yet reduces power in this band of anesthetized animals. Moreover, schizophrenics appear to have a significant increase in frontal delta oscillations when awake (Wuebben and Winterer, 2001), yet exhibit slow-wave sleep disturbances and lower delta count when asleep (Ganguli et al., 1987). How is that?

It may be a matter of perspective. In the awake state the cortex is highly desynchronized and firing is quite irregular with power in a variety of high-frequency bands and neurons firing at every phase angle of the field potential. With anesthetics, higher frequencies become unsustainable. Using realistic network model simulations, Durstewitz and Gabriel (2007) showed that if you come from a regime which is quite irregular and then reduce NMDA, you get clear delta wave oscillations, but as you keep reducing NMDA, these delta oscillations will become progressively reduced as well. So in the awake state, reductions in NMDA currents should relatively decrease power in many bands yet enhance delta, but if the network is already in delta, as when the subject is anesthetized or asleep, NMDA reduction would decrease power in this band. Therefore, the results of Kargieman et al., when viewed in light of the literature obtained in awake subjects and schizophrenics, confirms a non-trivial and somewhat paradoxical prediction of the NMDA theory of schizophrenia and the PCP model.

References:

Durstewitz D, Gabriel T. Dynamical basis of irregular spiking in NMDA-driven prefrontal cortex neurons. Cereb Cortex. 2007 Apr;17(4):894-908. Epub 2006 Jun 1. Abstract

Ganguli R, Reynolds CF 3rd, Kupfer DJ. Electroencephalographic sleep in young, never-medicated schizophrenics. A comparison with delusional and nondelusional depressives and with healthy controls. Arch Gen Psychiatry. 1987 Jan;44(1):36-44. Abstract

Marquis KL, Paquette NC, Gussio RP, Moreton JE. Comparative electroencephalographic and behavioral effects of phencyclidine, (+)-SKF-10,047 and MK-801 in rats. J Pharmacol Exp Ther. 1989 Dec;251(3):1104-12. Abstract

Matsuzaki M, Dowling KC. Phencyclidine (PCP): effects of acute and chronic administration on EEG activities in the rhesus monkey. Electroencephalogr Clin Neurophysiol. 1985 Apr;60(4):356-66. Abstract

Mattia A, Marquis KL, Leccese AP, el-Fakahany EE, Moreton JE. Electroencephalographic, behavioral and receptor binding correlates of phencyclinoids in the rat. J Pharmacol Exp Ther. 1988 Aug;246(2):797-802. Abstract

Sebban C, Tesolin-Decros B, Ciprian-Ollivier J, Perret L, Spedding M. Effects of phencyclidine (PCP) and MK 801 on the EEGq in the prefrontal cortex of conscious rats; antagonism by clozapine, and antagonists of AMPA-, alpha(1)- and 5-HT(2A)-receptors. Br J Pharmacol. 2002 Jan;135(1):65-78. Abstract

Stockard JJ, Werner SS, Aalbers JA, Chiappa KH. Electroencephalographic findings in phencyclidine intoxication. Arch Neurol. 1976 Mar;33(3):200-3. Abstract

Wuebben Y, Winterer G. Hypofrontality -- a risk-marker related to schizophrenia? Schizophr Res. 2001 Mar 30;48(2-3):207-17. Abstract

Yamamoto J. Cortical and hippocampal EEG power spectra in animal models of schizophrenia produced with methamphetamine, cocaine, and phencyclidine. Psychopharmacology (Berl). 1997 Jun;131(4):379-87. Abstract

I would like to underscore a point that emerges from the important paper by Saha and colleagues (an excellent summary is provided above by Victoria Wilcox). Currently the focus on inequalities/disparities in public health has paid attention mainly to socioeconomic and ethnic/racial disparities. This paper and some other recent papers draw attention to the disparities in health between people with and without severe mental illness. I view this disparity as being in large part rooted in discrimination experienced by people with mental illness, rather than being inherent in their illness. People with a severe mental illness should have the right to high quality health care and prevention, even if care and prevention has to be tailored to their special needs so that it can be utilized.

View all comments by Ezra Susser

Serotonin_2A Receptors and Schizophrenia: The Controversies Continue
A new study reporting decreased serotonin_2A receptor (HTR2A) density in drug naïve first-episode schizophrenia (Rasmussen et al., 2010) has again raised the issue of the role of that receptor in the pathophysiology of the disorder.

The notion that the HTR2A is involved in pathophysiology and treatment of schizophrenia remains an open issue. The observation that a number of the atypical antipsychotic drugs are high-affinity antagonists at the receptor would suggest that blocking stimulation of the receptor can have some therapeutic benefit (Meltzer, 1995). It is also significant that, overall, available data from postmortem studies would suggest that the HTR2A is decreased in density in the cortex of subjects with schizophrenia (Dean, 2003). This could either be due to altered gene expression per se or an appropriate agonist induced...  Read more

Serotonin_2A Receptors and Schizophrenia: The Controversies Continue
A new study reporting decreased serotonin_2A receptor (HTR2A) density in drug naïve first-episode schizophrenia (Rasmussen et al., 2010) has again raised the issue of the role of that receptor in the pathophysiology of the disorder.

The notion that the HTR2A is involved in pathophysiology and treatment of schizophrenia remains an open issue. The observation that a number of the atypical antipsychotic drugs are high-affinity antagonists at the receptor would suggest that blocking stimulation of the receptor can have some therapeutic benefit (Meltzer, 1995). It is also significant that, overall, available data from postmortem studies would suggest that the HTR2A is decreased in density in the cortex of subjects with schizophrenia (Dean, 2003). This could either be due to altered gene expression per se or an appropriate agonist induced downregulation of the receptor due to chronic overactivation (Rahimian et al., 1995). Recently, it has been suggested that different outcomes from the postmortem studies are due to differing methodologies (Dean et al., 2008); the differences being due to studies using particulate membrane separating a component in the cytosol which regulates receptor binding from the receptor protein. It is becoming clear that the HTR2A is part of protein complexes in the membrane (Gonzalez-Maeso et al., 2008), and, therefore, it could well be that further exploration of the interactions between the HTR2A and its membrane complexes as well as the cytosol are required to make postmortem data on the HTR2A more interpretable.

As with postmortem studies, positron emission tomography studies appear to be giving disparate outcomes regarding the levels of HTR2A in schizophrenia (Table 1). Clearly, in these studies different results cannot be accounted for by separating the receptor from intracellular regulatory proteins or membrane complexes. Moreover, whilst there are differences in the number of subjects in each study, an analysis of cohort sizes (Fisher exact test) shows this measure does not differ significantly across studies (p = 0.09). Finally, the radioligand used would not appear to be influencing outcomes, as studies using [¹⁸F]setoperone and [¹⁸F]altanserin have both given different outcomes in different studies of levels of HTR2A in subjects with schizophrenia.

One intriguing observation is that, if current studies are ranked by the mean age of the total cohort of subjects studied, then the two studies reporting decreases in the HTR2A in schizophrenia were completed on the youngest of the seven cohorts (Table 1). This raises the possibility that decreases in the HTR2A may be detectable by neuroimaging early in the disease process. If that is the case, could a decrease in cortical HTR2A be a potential prodromal marker to predict the transition from high risk to frank schizophrenia?

References:

Rasmussen, H, et al., (2010) Decreased frontal serotonin_2A receptor binding in antipsychotic-naive patients with first-episode schizophrenia, Arch. Gen. Psychiatry 67, 9-16. Abstract

Meltzer, HY, (1995) The role of serotonin in schizophrenia and the place of serotonin-dopamine antagonist antipsychotics, J. Clin. Psychopharmacol. 15, 2S-3S. Abstract

Dean, B, (2003) The cortical serotonin_2A receptor and the pathology of schizophrenia: a likely accomplice, J. Neurochem. 85, 1-13. Abstract

Rahimian, R, et al., (1995) Possible role of protein kinase C in regulation of 5-hydroxytryptamine 2A receptors in rat brain, Can. J. Physiol Pharmacol. 73, 1686-1691. Abstract

Dean, B, et al., (2008) Evidence for altered post-receptor modulation of the serotonin 2a receptor in schizophrenia, Schizophr. Res. 104, 185-197. Abstract

Gonzalez-Maeso, J, et al., (2008) Identification of a serotonin/glutamate receptor complex implicated in psychosis, Nature 452, 93-97. Abstract

Ngan, ET, et al., (2000) Decreased serotonin 2A receptor densities in neuroleptic-naive patients with schizophrenia: A PET study using [(18)F]setoperone, Am. J. Psychiatry 157, 1016-1018. Abstract

Okubo, Y, et al., (2000) Serotonin 5-HT2 receptors in schizophrenic patients studied by positron emission tomography, Life Sci. 66, 2455-2464. Abstract

Trichard, C, et al., (1998) No serotonin 5-HT2A receptor density abnormality in the cortex of schizophrenic patients studied with PET, Schizophr. Res. 31, 13-17. Abstract

Erritzoe, D, et al., (2008) Cortical and subcortical 5-HT2A receptor binding in neuroleptic-naive first-episode schizophrenic patients, Neuropsychopharmacology 33, 2435-2441. Abstract

Lewis, R, et al., (1999) Serotonin 5-HT2 receptors in schizophrenia: a PET study using [18F]setoperone in neuroleptic-naive patients and normal subjects, Am. J. Psychiatry 156, 72-78. Abstract

Verhoeff, NP, et al., (2000) A voxel-by-voxel analysis of [18F]setoperone PET data shows no substantial serotonin 5-HT(2A) receptor changes in schizophrenia, Psychiatry Res. 99, 123-135. Abstract

The search for biomarkers in complex psychiatric disorders such as schizophrenia has been a crucial goal in clinical research, but remains to be fully accomplished. Serotonin 5-HT_2A receptors have been associated with the pathophysiology and pharmacotherapy of schizophrenia for two main reasons: 5-HT_2A receptor agonists such as LSD elicit hallucinogenic states in humans and second-generation, atypical antipsychotics are effective 5-HT_2A receptor antagonists. However, 5-HT_2A receptor agonists usually evoke visual hallucinations, whereas those associated with schizophrenia are commonly auditory (Hollister, 1962). Contradictory changes in 5-HT_2A receptor density in cortical areas of the brain have been detected in several postmortem studies. The case-control study of Rasmussen and coworkers (Rasmussen et al., 2010) shows decreased 5-HT_2A binding in the frontal cortex of antipsychotic-free, first-episode schizophrenics. Although similar findings were previously observed...  Read more

The search for biomarkers in complex psychiatric disorders such as schizophrenia has been a crucial goal in clinical research, but remains to be fully accomplished. Serotonin 5-HT_2A receptors have been associated with the pathophysiology and pharmacotherapy of schizophrenia for two main reasons: 5-HT_2A receptor agonists such as LSD elicit hallucinogenic states in humans and second-generation, atypical antipsychotics are effective 5-HT_2A receptor antagonists. However, 5-HT_2A receptor agonists usually evoke visual hallucinations, whereas those associated with schizophrenia are commonly auditory (Hollister, 1962). Contradictory changes in 5-HT_2A receptor density in cortical areas of the brain have been detected in several postmortem studies. The case-control study of Rasmussen and coworkers (Rasmussen et al., 2010) shows decreased 5-HT_2A binding in the frontal cortex of antipsychotic-free, first-episode schizophrenics. Although similar findings were previously observed (Ngan et al., 2000; Erritzoe et al., 2008), the present study used the largest sample of patients to date, which gives further strength and validity to the results.

A question that remains to be answered is, What causes this reduced 5-HT_2A binding? Although a hyperactive serotonergic transmission in the prefrontal cortex has been implicated in schizophrenia (Meltzer, 1989), the precise role of cortical serotonin on this effect is not fully understood. It has been shown in an animal model of the illness that antagonists of the NMDA glutamate receptor increased serotonin release in prefrontal cortex (Adams and Moghaddam, 2001; Amargós-Bosch et al., 2006; López-Gil et al., 2007), an effect prevented by atypical but not typical antipsychotic drugs (López-Gil et al., 2007; 2010). If these changes also occur in schizophrenia, the decreased 5-HT_2A binding might be a compensatory effect resulting from increased cortical serotonergic transmission. Interestingly, although negative symptoms are usually thought to be associated with impaired serotonergic transmission in schizophrenia (Reynolds, 2004), the present study found a significant negative correlation between 5-HT_2A binding in the frontal cortex and positive symptoms in the group of male patients. A study with a larger population is likely needed to draw unequivocal conclusions on that matter. Also, an important point not to be missed is that PET measures were performed, for obvious reasons, in a resting state. Differences in serotonergic changes may thus exist, depending on the pathological phase of the illness.

From a pharmacological point of view, it is worth noting that blockade of 5-HT_2A receptors alone does not confer antipsychotic activity. Thus, clinical evaluation of the selective 5-HT_2A antagonist, M100907, failed to demonstrate therapeutic efficacy (de Paulis, 2001), despite the high level of 5-HT_2A receptor occupancy achieved in frontal cortex (Offord et al., 1999). With the exception of dopamine D2 receptor antagonists (Seeman et al., 1976), no other monoamine receptor antagonist has been shown to possess antipsychotic activity per se. Therefore, there is a clear need for targeting different transmitter receptors in order to achieve better treatment (as well as a lower side effect profile) of schizophrenia. What the study by Rasmussen and coworkers clearly points out is that 5-HT_2A receptors in the frontal cortex are involved in the pathophysiology of schizophrenia, and this region plays a role in the pharmacological effects of antipsychotic drugs.

References:

Adams BW, Moghaddam B. Effect of clozapine, haloperidol, or M100907 on phencyclidine-activated glutamate efflux in the prefrontal cortex. Biol Psychiatry. 2001;50:750–757. Abstract

Amargós-Bosch M, López-Gil X, Artigas F, Adell A. Clozapine and olanzapine, but not haloperidol, suppress serotonin efflux in the medial prefrontal cortex elicited by phencyclidine and ketamine. Int J Neuropsychopharmacol. 2006;9:565–573. Abstract

De Paulis T. M-100907 (Aventis). Curr Opin Investig Drugs. 2001;2:123-132. Abstract

Erritzoe D, Rasmussen H, Kristiansen KT, Frokjaer VG, Haugbol S, Pinborg L, Baaré W, Svarer C, Madsen J, Lublin H, Knudsen GM, Glenthoj BY. Cortical and subcortical 5-HT2A receptor binding in neuroleptic-naïve first-episode schizophrenic patients. Neuropsychopharmacology. 2008;33:2435-2441. Abstract

López-Gil X, Babot Z, Amargós-Bosch M, Suñol C, Artigas F, Adell A. Clozapine and haloperidol differently suppress the MK-801-increased glutamatergic and serotonergic transmission in the medial prefrontal cortex of the rat. Neuropsychopharmacology. 2007;32:2087-97. Abstract

López-Gil X, Artigas F, Adell A. Unraveling monoamine receptors involved in the action of typical and atypical antipsychotics on glutamatergic and serotonergic transmission in prefrontal cortex. Curr Pharm Des. 2010. Abstract

Meltzer HY. Clinical studies on the mechanism of action of clozapine: the dopamine-serotonin hypothesis of schizophrenia. Psychopharmacology. 1989;99. S18–S27. Abstract

Ngan ET, Yatham LN, Ruth TJ, Liddle PF. Decreased serotonin 2A receptor densities in neuroleptic-naïve patients with schizophrenia: a PET study using [18F]setoperone. Am J Psychiatry. 2000;157:1016-1018. Abstract

Offord SJ, Wong DF, Nyberg S. The role of positron emission tomography in the drug development of M100907, a putative antipsychotic with a novel mechanism of action. J Clin Pharmacol. 1999;39:17S-24S. Abstract

Rasmussen H, Erritzoe D, Andersen R, Ebdrup BH, Aggernaes B, Oranje B, Kalbitzer J, Madsen J. Decreased frontal serotonin2A receptor binding in antipsychotic-naïve patients with first-episode schizophrenia. Arch Gen Psychiatry. 2010;67:9-16. Abstract

Reynolds GP. Receptor mechanisms in the treatment of schizophrenia. J Psychopharmacol. 2004;18:340-345. Abstract

Seeman P, Lee T, Chau-Wong M, Wong K. Antipsychotic drug doses and neuroleptic/dopamine receptors. Nature. 1976;261:717-719. Abstract

Mechanisms of Capacity Limitations in Working Memory
Gold and colleagues have provided an extremely elegant example of how a precisely controlled behavioral study can be used to directly test implications generated by neurobiological theories of cognitive impairment in schizophrenia. Further, they have provided novel and important data in schizophrenia that should cause us to re-examine theories about the mechanisms underling working memory impairments in this illness.

As noted by Gold, it has been hypothesized that altered GABAergic, glutamatergic, and/or dopaminergic inputs into reverberating and oscillatory networks in prefrontal or parietal cortex among individuals with schizophrenia should render such networks unstable and lead to less precise working memory representations that are particularly prone to decay (Lisman et al., 2008; Durstewitz and Seamans, 2008; Rolls et al., 2008;   Read more

Mechanisms of Capacity Limitations in Working Memory
Gold and colleagues have provided an extremely elegant example of how a precisely controlled behavioral study can be used to directly test implications generated by neurobiological theories of cognitive impairment in schizophrenia. Further, they have provided novel and important data in schizophrenia that should cause us to re-examine theories about the mechanisms underling working memory impairments in this illness.

As noted by Gold, it has been hypothesized that altered GABAergic, glutamatergic, and/or dopaminergic inputs into reverberating and oscillatory networks in prefrontal or parietal cortex among individuals with schizophrenia should render such networks unstable and lead to less precise working memory representations that are particularly prone to decay (Lisman et al., 2008; Durstewitz and Seamans, 2008; Rolls et al., 2008; Lewis et al., 2008). However, Gold and colleagues have shown that working memory representations in schizophrenia (at least of color memory) are neither less precise nor show evidence of exceptionally rapid decay. Instead, individuals with schizophrenia showed clearly reduced working memory capacity.

These data contribute to a systemic body of work generated by Gold and colleagues, who have investigated the many aspects of working memory that could be impaired in schizophrenia. They have also shown that iconic decay is not increased in schizophrenia (Hahn et al., 2010), that feature binding is intact (Gold et al., 2003), and that certain aspects of attentional control over working memory are intact (Gold et al., 2006), though others are impaired (Fuller et al., 2006). However, working memory capacity has consistently been shown to be reduced in schizophrenia across numerous studies (Gold et al., 2006; van Raalten et al., 2008; Silver et al., 2003). If we take these results seriously (and we should), they require us to look closely at the neural mechanisms postulated to modulate capacity limitations in working memory in order to generate clues to the mechanisms that may be leading to reduced working memory capacity in schizophrenia.

The neural mechanisms leading to working memory capacity limitations are still very much an open source of debate. However, one influential theory is that the number of “items” that can be maintained in working memory is limited by the number of gamma cycles (30-100 Hz) that can be embedded within a theta cycle (Lisman, 2010). Related to the idea that originally drove the design of the Gold study, Lisman and others have hypothesized that individual items within working memory are represented by oscillating neural populations with spike rates phase-locked in a gamma cycle. The oscillatory activity representing different items must be kept isolated, potentially by keeping gamma activity for different items out of phase with each other. One way to accomplish this would be to couple such gamma cycles into a lower frequency theta oscillation that can help regulate and separate activity associated with different items (as well as maintain information about order). Lisman and others have argued that capacity constraints of approximately four items in working memory (Cowan, 2001) thus reflect the number of gamma cycles that can be embedded in a theta cycle (approximately four) (Lisman, 2010; Wolters and Raffone, 2008).

Gold’s results suggest that it may not be the maintenance of the individual gamma-oscillating neural populations representing individual items that is impaired in schizophrenia. Instead, it may be either the ability to establish such synchronous neural activity associated with a specific item, or the ability to couple a number of different gamma-oscillating sub-networks into a theta cycle. Interestingly, a growing number of studies have shown altered gamma activity during working memory in schizophrenia (Barr et al., 2010; Basar-Eroglu et al., 2007; Light et al., 2006; Kissler et al., 2000), as well as some evidence for altered theta activity (Haenschel et al., 2009). However, additional work is needed to specifically examine gamma-theta coupling in schizophrenia and its role in determining capacity limitations in this disease.

The type of network models of working memory put forth by Wang and colleagues suggest that the dynamics of excitatory and inhibitory inputs drive the number of independent “activity bumps” (i.e., items) that can be maintained in a network (Compte et al., 2000). A related idea about the mechanisms driving capacity limitations and variations in these limits across individuals has been put forth by Klingberg and colleagues, who have argued that the dynamics of such lateral inhibitory mechanisms in parietal cortex limit memory capacity to be between two and seven items (Edin et al., 2009). However, they have also argued that such capacity limits can be overcome, at least temporarily, by excitatory inputs into parietal cortex from prefrontal cortex (Edin et al., 2009). They have suggested that this provides a mechanistic account of top-down control over working memory capacity by prefrontal cortex. As such, given the evidence for at least some types of abnormalities in top-down control of attention in schizophrenia (Fuller et al., 2006; Hahn et al., 2010), and evidence for altered connectivity between prefrontal and parietal regions (Barch and Csernansky, 2007; Karlsgodt et al., 2008), another possible source of reduced capacity in working memory in schizophrenia may be a reduction in prefrontal-mediated excitatory input into parietal networks that maintain items in working memory.

One might argue that the same GABA, glutamate, or dopamine mechanisms thought to impair the maintenance of representations in working memory could also impair the initial establishment of gamma oscillating networks representing items, their coupling to a lower-frequency theta cycle, or even the ability of prefrontal cortex to provide excitatory inputs into neural networks supporting the representation of items in working memory. If so, such models will also need to explain how such impairments could lead to reduced working memory capacity in schizophrenia without a change in precision or decay, a challenge for most current neural network models of working memory. As such, the data provided by Gold and colleagues suggest an exciting new pathway for research on working memory in schizophrenia that may allow us to develop more precise mechanistic hypotheses as to the source of these cognitive impairments and their relationship to pathophysiology of this illness.

References
Lisman JE, Coyle JT, Green RW, Javitt DC, Benes FM, Heckers S, Grace AA. Circuit-based framework for understanding neurotransmitter and risk gene interactions in schizophrenia. Trends Neurosci. 2008;31(5):234-42. Abstract

Durstewitz D, Seamans JK. The dual-state theory of prefrontal cortex dopamine function with relevance to catechol-o-methyltransferase genotypes and schizophrenia. Biol Psychiatry. 2008;64(9):739-49. Abstract

Rolls ET, Loh M, Deco G, Winterer G. Computational models of schizophrenia and dopamine modulation in the prefrontal cortex. Nat Rev Neurosci. 2008;9(9):696-709. Abstract

Lewis DA, Cho RY, Carter CS, Eklund K, Forster S, Kelly MA, Montrose D. Subunit-selective modulation of GABA type A receptor neurotransmission and cognition in schizophrenia. Am J Psychiatry. 2008;165(12):1585-93. Abstract

Hahn B, Kappenman ES, Robinson BM, Fuller RL, Luck SJ, Gold JM. Iconic Decay in Schizophrenia. Schizophr Bull. 2010. 2010 Jan 6. Abstract

Gold JM, Wilk CM, McMahon RP, Buchanan RW, Luck SJ. Working memory for visual features and conjunctions in schizophrenia. J Abnorm Psychol. 2003;112(1):61-71. Abstract

Fuller RL, Luck SJ, Braun EL, Robinson BM, McMahon RP, Gold JM. Impaired control of visual attention in schizophrenia. J Abnorm Psychol. 2006;115(2):266-75. Abstract

Gold JM, Fuller RL, Robinson BM, McMahon RP, Braun EL, Luck SJ. Intact attentional control of working memory encoding in schizophrenia. J Abnorm Psychol. 2006;115(4):658-73. Abstract

van Raalten TR, Ramsey NF, Jansma JM, Jager G, Kahn RS. Automatization and working memory capacity in schizophrenia. Schizophr Res. 2008;100(1-3):161-71. Abstract

Silver H, Feldman P, Bilker W, Gur RC. Working memory deficit as a core neuropsychological dysfunction in schizophrenia. Am J Psychiatry. 2003;160(10):1809-16. Abstract

Lisman J. Working memory: the importance of theta and gamma oscillations. Curr Biol. 2010;20(11):R490-2. Abstract

Cowan N. The magical number 4 in short-term memory: A reconsideration of mental storage capacity. Behav Brain Sci. 2001;24:87-114. Abstract

Wolters G, Raffone A. Coherence and recurrency: maintenance, control and integration in working memory. Cogn Process. 2008;9(1):1-17. Abstract

Barr MS, Farzan F, Tran LC, Chen R, Fitzgerald PB, Daskalakis ZJ. Evidence for excessive frontal evoked gamma oscillatory activity in schizophrenia during working memory. Schizophr Res. 2010. Abstract

Basar-Eroglu C, Brand A, Hildebrandt H, Karolina Kedzior K, Mathes B, Schmiedt C. Working memory related gamma oscillations in schizophrenia patients. Int J Psychophysiol. 2007;64(1):39-45. Abstract

Light GA, Hsu JL, Hsieh MH, Meyer-Gomes K, Sprock J, Swerdlow NR, Braff DL. Gamma band oscillations reveal neural network cortical coherence dysfunction in schizophrenia patients. Biol Psychiatry. 2006;60(11):1231-40. Abstract

Kissler J, Muller MM, Fehr T, Rockstroh B, Elbert T. MEG gamma band activity in schizophrenia patients and healthy subjects in a mental arithmetic task and at rest. Clin Neurophysiol. 2000;111(11):2079-87. Abstract

Haenschel C, Bittner RA, Waltz J, Haertling F, Wibral M, Singer W, Linden DE, Rodriguez E. Cortical oscillatory activity is critical for working memory as revealed by deficits in early-onset schizophrenia. J Neurosci. 2009;29(30):9481-9. Abstract

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Since the John Davis meta-analysis in the 1970s (the second meta-analysis in medicine; see Davis, 1975), there is little doubt that drug beats placebo in relapse prevention. What is terrific here are the details on aspects of course that are addressed and more information on the risk side to complement benefit. I will comment on two findings. First, depot beats oral. Especially in the United States, we need to move depot into an attractive option and first-line approach (assuming oral administration of the same compound supports safety in the individual). Second, I have thought that there is little evidence for second-generation antipsychotics being superior to first-generation antipsychotics (clozapine excepted) in efficacy and effectiveness, and that the strongest case for second-generation antipsychotics was better relapse prevention. This meta-analysis failed to support this supposed advantage, and I have to adjust my view in this regard.

The van Os and Howes commentary merits a serious and thoughtful read. It gives...  Read more

Since the John Davis meta-analysis in the 1970s (the second meta-analysis in medicine; see Davis, 1975), there is little doubt that drug beats placebo in relapse prevention. What is terrific here are the details on aspects of course that are addressed and more information on the risk side to complement benefit. I will comment on two findings. First, depot beats oral. Especially in the United States, we need to move depot into an attractive option and first-line approach (assuming oral administration of the same compound supports safety in the individual). Second, I have thought that there is little evidence for second-generation antipsychotics being superior to first-generation antipsychotics (clozapine excepted) in efficacy and effectiveness, and that the strongest case for second-generation antipsychotics was better relapse prevention. This meta-analysis failed to support this supposed advantage, and I have to adjust my view in this regard.

The van Os and Howes commentary merits a serious and thoughtful read. It gives emphasis to how early and modest the field is in discovery for the psychopharmacology of schizophrenia. In the 60 years since chlorpromazine, progress has been narrow, not very innovative, and not very robust.

References:

Davis JM. Overview: maintenance therapy in psychiatry: I. Schizophrenia. Am J Psychiatry . 1975 Dec ; 132(12):1237-45. Abstract

Antipsychotics are (generally) effective in relapse prevention—however, evidence-based indicators for more individualized treatment are needed.

Leucht and colleagues (Leucht et al., 2012) conducted a new, highly comprehensive, but also very differentiated meta-analysis on the relapse preventive efficacy of antipsychotic drugs as compared to placebo, which is now published in The Lancet. In addition, detailed comments are provided by van Os and Howes (van Os and Howes, 2012) in the same issue. As in former reviews addressing this topic, the results clearly underline that antipsychotics are (generally) effective in preventing relapse in schizophrenia compared to placebo with average one-year relapse rates of 27 percent versus 64 percent, an estimated risk ratio of 0.4, and a number of 3 needed to treat (to benefit) patients. On the other hand, and despite this high-grade evidence, many patients with schizophrenia still show cognitive, affective, motivational, or "functional"...  Read more

Antipsychotics are (generally) effective in relapse prevention—however, evidence-based indicators for more individualized treatment are needed.

Leucht and colleagues (Leucht et al., 2012) conducted a new, highly comprehensive, but also very differentiated meta-analysis on the relapse preventive efficacy of antipsychotic drugs as compared to placebo, which is now published in The Lancet. In addition, detailed comments are provided by van Os and Howes (van Os and Howes, 2012) in the same issue. As in former reviews addressing this topic, the results clearly underline that antipsychotics are (generally) effective in preventing relapse in schizophrenia compared to placebo with average one-year relapse rates of 27 percent versus 64 percent, an estimated risk ratio of 0.4, and a number of 3 needed to treat (to benefit) patients. On the other hand, and despite this high-grade evidence, many patients with schizophrenia still show cognitive, affective, motivational, or "functional" deficits and impairments in the longer illness course. This indicates that antipsychotics are not so effective in all symptom domains and contributes to the notion by some researchers that schizophrenia is still a "poor outcome" disorder, in particular as compared to other mental disorders (Jobe and Harrow, 2005). Thus, further efforts are needed to develop drug and other treatment strategies to affect the illness course more comprehensively. In this regard, a more uniform and broadly accepted definition of "relapse" would be very helpful. For example, the consensus-based definition of "remission" (Andreasen et al., 2005) has stimulated a large amount of research and enables a better comparison of results across studies.

Some other aspects are noteworthy to address. First, it is still unclear how long antipsychotic treatment has to be maintained, especially after a first episode. A comparison of evidence-based treatment guidelines from different countries developed on highest-quality criteria yielded no or inconsistent recommendations regarding the duration of maintenance treatment (Gaebel et al., 2011). In the last years, different trials compared maintenance treatment (MT) with (stepwise) drug discontinuation (mostly supplemented by early drug intervention based on early signs for relapse, i.e., targeted intermittent treatment/IT) in the long-term treatment of first-episode patients. Whether drug treatment was discontinued after six months (Wunderink et al., 2007), after one year (Gaebel et al., 2011), or, as just published, after two years (Emsley et al., 2012; observational design after drug discontinuation), risk for relapse did noticeably increase after drug discontinuation (up to fivefold after one year compared to further MT). On the other hand, a considerable proportion of patients remains stable under intermittent treatment (in the Gaebel et al., 2011, trial, about 50 percent after MT in the first year). In addition, a relevant proportion of patients (about 20 percent) remain relapse free and develop only one illness episode also if drug treatment was suspended (e.g., Harrow et al., 2012).

There are other significant findings indicating that different patients respond differently to similar treatment strategies. Although efficacy of antipsychotics in general is proven, a distinct proportion of patients suffers from partial remission, symptom recurrence, or relapse despite antipsychotic treatment. This applies also to depot treatment, which minimizes adherence problems, although some patients do relapse, as once again shown in a recent placebo-controlled trial not yet included in the Leucht review (Kane et al., 2012). Similarly, the inconclusive results regarding abrupt versus stepwise drug discontinuation and the development of a "supersensitivity" psychosis represent (to a great extent) different effects in different patients. This corresponds to a finding of our own discontinuation trial, in which assured pre-treatment with antipsychotics and an excellent treatment response have been predictors for deterioration in the case of drug discontinuation (Gaebel et al., 2011). It seems that some patients do very well with antipsychotics (often mistaken by themselves as not being in need of drugs), and that they are the ones who should be recommended to rather maintain than to discontinue treatment.

Based on the Vulnerability-Stress-Coping-model for schizophrenia, many influencing factors contribute to illness development and course. Accordingly, schizophrenia represents a heterogeneous illness due to various pathogenetic factors. Thus, different effects in different patients to similar treatment strategies are to be expected. On the other hand, different antipsychotics do also show some differences in efficacy on different symptom domains (Leucht et al., 2009), as well as in side effect and receptor profiles (Correll, 2010). Thus, besides developing new drugs and other treatment strategies, research should also focus on matching the right patient to the right treatment strategy. This requires the availability of valid (i.e., evidence-based) indicators to enable effective individual treatment decisions. This could be clinical indicators (like symptom characteristics, response, adherence, etc.) or biological markers such as genetic variants, neurophysiological, chemical, or functional parameters (among others). For example, Mössner et al. (Mössner et al., 2009) analyzed data from the first-episode study incorporating the above-mentioned discontinuation trial (Gaebel et al., 2011) regarding genetic characteristics and drug response. They found that response in the negative symptom domain is different according to a common polymorphism (-1019C/G) located in the promoter region of the serotonin (5-HT) 1A receptor gene only for the SGA risperidone (as compared to haloperidol). Other observational trials show similar effects, but well-controlled RCTs are needed to provide sound evidence. Accordingly, we are now preparing a trial in which patients with primary negative symptoms are randomly allocated to different SGAs to investigate response differences in the negative symptom domain in relation to their (-1019C/G) polymorphisms.

References:

Leucht S, Tardy M, Komossa K, Heres S, Kissling W, Salanti G, Davis JM (2012). Antipsychotic drugs versus placebo for relapse prevention in schizophrenia: a systematic review and meta-analysis. Lancet. 379:2063-71. Abstract

van Os J, Howes OD (2012). Antipsychotic drugs for prevention of relapse. Lancet. 2012; 379):2030-1. Abstract

Jobe TH, Harrow M. Long-term outcome of patients with schizophrenia: a review. Canadian Journal of Psychiatry. 2005; 50, 892-900. Abstract

Andreasen NC, Carpenter WT, Kane JM, Lasser RA, Marder SR, Weinberger DR. Remission in schizophrenia: proposed criteria and rationale for consensus. Am J Psychiatry 2005;62:441-449. Abstract

Gaebel W, Riesbeck M, Wobrock T (2011): Schizophrenia guidelines across the world: a selective review and comparison. Int Rev Psychiatry. 23: 379-87. Abstract

Wunderink L, Nienhuis FJ, Sytema S, Slooff CJ, Knegtering R, Wiersma D. Guided discontinuation versus maintenance treatment in remitted first-episode psychosis: relapse rates and functional outcome. J Clin Psychiatry, 2007, 68:654-61. Abstract

Gaebel W, Riesbeck M, Wölwer W, Klimke A, Eickhoff M, von Wilmsdorff M, Lemke M, Heuser I, Maier W, Huff W, Schmitt A, Sauer H, Riedel M, Klingberg S, Köpcke W, Ohmann C, Möller HJ; German Study Group on First-Episode Schizophrenia (2011): Relapse prevention in first-episode schizophrenia: Maintenance vs. intermittent drug treatment with prodrome-based early intervention. Results of a randomized controlled trial within the German Research Network on Schizophrenia. J Clin Psychiatry. 72: 205-18. Abstract

Emsley R, Oosthuizen PP, Koen L, Niehaus DJ, Martinez G (2012). Symptom recurrence following intermittent treatment in first-episode schizophrenia successfully treated for 2 years: a 3-year open-label clinical study. J Clin Psychiatry. 73: e541-e547. Abstract

Harrow M, Jobe TH, Faull RN. Do all schizophrenia patients need antipsychotic treatment continuously throughout their lifetime? A 20-year longitudinal study. Psychol Med. 2012 Feb 17:1-11. Abstract

Kane JM, Sanchez R, Perry PP, Jin N, Johnson BR, Forbes RA, McQuade RD, Carson WH, Fleischhacker WW. Aripiprazole Intramuscular Depot as Maintenance Treatment in Patients With Schizophrenia: A 52-Week, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study. J Clin Psychiatry 2012;73(5):617-624. Abstract

Leucht S, Corves C, Arbter D, Engel RR, Li C, Davis JM (2009). Second-generation versus first-generation antipsychotic drugs for schizophrenia: a meta-analysis. Lancet; 373: 31-41. Abstract

Correll CU (2010). From receptor pharmacology to improved outcomes: individualising the selection, dosing, and switching of antipsychotics. Eur Psychiatry. 25 Suppl 2:S12-21. Abstract

Mössner R, Schuhmacher A, Kühn KU, Cvetanovska G, Rujescu D, Zill P, Quednow BB, Rietschel M, Wölwer W, Gaebel W, Wagner M, Maier W (2009). Functional serotonin 1A receptor variant influences treatment response to atypical antipsychotics in schizophrenia. Pharmacogenet Genomics;19:91-4. Abstract