Based on a study of 227 subjects, Jones and colleagues...
Based on a study of 227 subjects, Jones and colleagues conclude that “there is no disadvantage …in commencing treatment with FGAs rather than atypical SGAs in people with schizophrena…” (Jones et al., 2006). Jones et al chose to compare two groups (all FGAs v.all SGAs). Although they acknowledge, in general, within-group heterogeneity, they consider the comparison between groups clinically useful. However, this perspective that in fact ignores the heterogeneity is limiting, and, in combination with the results of the study, might encourage clinicians to believe that the effectiveness of all antipsychotics is equal (with the possible exception of clozapine).
A recent report provided evidence of great variability of effectiveness across the spectrum of FGAs and SGAs (Tiihonen et al., 2006). This was an observational prospective cohort study of 2230 adults hospitalized for schizophrenia in Finland. The main outcome measures were rates of discontinuation of treatment, and rehospitalization. The study found that the effectiveness within the FGA group varied as a function of route of administration Perphenazine decanoate (the only depot drug analyzed) was considerably more effective than the oral form of the same drug,; in fact, it appeared to be superior to any other drug in the study, including clozapine. Furthermore, clozapine and olanzapine showed better effectiveness than haloperidol . Other drugs in the study (FGAs and SGAs) showed inconsistent differences from haloperidol. Thus, the effectiveness af antipsychotics is not equal.
Nevertheless, in spite of methodological differences, the Jones and Tihonen studies are consistent with each other. Had Tiihonen et al. elected to create and compare two groups analogous to the Jones study (FGAs v. SGAs), the result might have been the same as shown by Jones et al: no group difference (see Tiihonen tables showing the treatments ordered by the relative risks of rehospitalization and discontinuation). This result, if presented as the sole outcome of the study, would have obscured very important differences among individual drugs.
What, then, is the useful clinical perspective based on all these data? I think that the success of perphenazine decanoate in the Tiihonen study brings up again the great importance of compliance for effectiveness. Furthermore, the choice of drug for individual patients should probably be driven by the individual properties of the drug and of the patient, rather than by the drug’s classification.
Do the SGAs exhibit greater effectiveness than the FGAs? At this stage of the game, we may seek refuge with Orwell: All antipsychotics are equal, but some antipsychotics are more equal than others.
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