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ICOSR 2013—Exploring Variation in Schizophrenia Around the Globe

23 Apr 2013

24 April 2013. As part of our ongoing coverage of the 2013 International Congress on Schizophrenia Research (ICOSR), held 21-25 April in Orlando, Florida, we bring you session summaries from some of the Young Investigator travel award winners. We are, as always, grateful for the gracious assistance of conference directors Carol Tamminga and Chuck Schulz, as well as meeting staff Cristan Tamminga and Dorothy Denton. For this report, we thank James Kirkbride of the University of Cambridge, United Kingdom.

The symposium The Earth Is Not Flat: Gradients in the Epidemiology of Schizophrenia Across the Globe, dynamically organized by John McGrath of the Queensland Centre for Mental Health Research, Australia, continued to pave the way for embracing variance in the epidemiological landscape of schizophrenia in the search for etiological risk factors for psychosis in the environment. During the first decade of the new millennium, McGrath and others have rejuvenated interest in our understanding of heterogeneity in incidence rates, course, and outcome of psychotic disorders across the globe (McGrath, 2008; McGrath et al., 2004; Mortensen et al., 1999; Lewis et al., 1992; Morgan et al., 2010; Kirkbride et al., 2012). But for the large part of this decade, the epidemiological landscape was dominated by a few influential studies from Northern European settings. We have learned tremendously from these studies: rates are higher in urban areas (Kirkbride et al., 2006), urban birth is a risk factor for later disorder (Mortensen et al., 1999), some migrants and their offspring face elevated rates of psychotic disorders (Cantor-Graae and Selten, 2005), and this risk may be conditional upon neighborhood composition (Veling et al., 2008). But for all these accomplishments, we have lacked true heterogeneity in research settings, with notable absences in empirical evidence from regions outside of the traditional bastions of psychosis epidemiology—the U.K., Netherlands, Scandinavia, and Australia.

But the “Earth Is Not Flat” session revealed how this research landscape is now changing, to be more diverse and explore the full range of epidemiological variance in psychosis, using carefully designed research from diverse settings, including Italy (both in Sicily and Bologna Tarricone et al., 2012), Brasil (Sao Paulo; Menezes et al., 2007, and shortly Ribeirao Preto), Nigeria, Jamaica (Hickling and Rodgers-Johnson, 1995), and India (Chennai). Alice Mule, University of Palermo, Italy, began the session by presenting new incidence findings from the SGAP study in Palermo. Using careful inclusion and case ascertainment criteria in a defined catchment area, Mule estimated that the incidence of all first-episode psychoses was around 15 new cases per 100,000 person-years, low compared with rates from the U.K. Craig Morgan wisely cautioned that studies such as AESOP in the U.K. (Kirkbride et al., 2006), where rates were twice as high as in Palermo, should not be held as any gold standard in terms of absolute incidence. If genuine, differences such as those between Southern and Northern Europe may hold vital clues to social or environmental factors underlying the epidemiology of schizophrenia (McGrath, 1999; Brown and Derkits, 2010; Birchwood et al., 1992). James Kirkbride noted that the incidence in the white British group in the U.K. AESOP study was in the region of 20 new cases per 100,000 person-years (Fearon et al., 2006), closer to the rate observed in Palermo, where immigrants only account for 3 percent of the population.

Paulo Menezes of the University of São Paulo, Brazil, presented further data from his first-episode psychosis study in São Paolo (Menezes et al., 2007). As in Palermo, the overall incidence of FEP was lower than rates in Northern Europe. Interestingly, Menezes showed how Brazil is undergoing rapid sociodemographic and economic change, with marked social inequality, an aging population, rapid urbanization, and changing ethnicity away from the majority white Caucasian group. While too early to say what effect these changes will have on the incidence of schizophrenia, Menezes is not remaining idle, setting up a new first-episode psychosis study in a second, smaller city inland of São Paolo, Ribeirao Preta. This study should pave the way for future investigations of rates in dramatically changing societies as well as understanding contextual differences in social or physical environments in new settings. During the Q&A period, Robin Murray summarized the incidence difference with intrigue, proposing that the lower rates in São Paolo and Sicily (compared with Northern Europe) could potentially be attributable to a range of factors requiring further research: family structure, religion, social fragmentation and cohesion, industrialization and infection, religion, vitamin D. Ezra Susser suggested that, given comparable levels of urbanicity between São Paolo and London, explanations for their differences in incidence had to be more plausibly explained by social rather than biological (i.e., infection, nutrition) differences.

One growing challenge for psychosis epidemiology is the study of psychotic disorders in low and middle income countries (LAMIC) (Esan et al., 2012; Rangaswamy and Gureje, 2012; Gureje and Cohen, 2011). In his beautifully crafted talk, Oye Gureje, University of Ibadan, Nigeria, highlighted the many methodological challenges of investigating the incidence of schizophrenia in Nigeria. Here, a solid epidemiological framework needs to underpin complex, sensitive adaptations in study design to successfully detect the true incidence of psychotic disorder in the population. Central to this, case ascertainment needs to be multifaceted, working with both formal care facilities and complementary and alternative practitioners, who need to be engaged as partners in such research efforts. Prior to any epidemiological fieldwork, Gureje emphasizes, there is a need to conduct qualitative research in the community to fully understand what people understand by psychosis, and how its presentation and phenomenology may differ within and between settings. He is engaged in several psychosis studies of both incidence and outcomes, including SCALP (SCALing up services for people with Psychosis), PaM-D (Partnerships for Mental Health Development in Sub-Saharan Africa), and INTREPID, the last of which is a major collaboration among researchers in Nigeria, Jamaica, the U.K., and India.

The final speaker in the session was Rangaswamy Thara, of the Schizophrenia Research Foundation of Chennai, India, who spoke about the complexities and challenges of designing and conducting psychiatric research in India, with a population of 1.2 billion people and little mental health research infrastructure or investment. Thara has worked tirelessly to establish epidemiological studies in India, overcoming substantial barriers to research in the process (Thara and Sujit, 2013). Forty percent of people with schizophrenia in India do not receive treatment, and several problems, including stigma, misconceptions about mental illness and its treatment, a lack of disability benefits, and poor care facilities mean that the axiom of better course and outcome in LAMIC is in urgent need of questioning (Cohen et al., 2008). Thara called for young researchers to embrace this call, to conduct high-quality research in these settings, to deconstruct the evidence surrounding this notion (Thornicroft et al., 2010). Several studies in India are underway, including a First-Episode Psychosis program in conjunction with the Douglas Institute, McGill University (Canada), lay worker treatment training programs, and psychiatric genetic research studies. See the Schizophrenia Research Foundation India for more information on such research.

There is a clear need to elucidate the epidemiology of psychotic disorders across the full continuum of environments, between and within national contexts. Luckily, the rich contours of epidemiology detected in Northern Europe over the last 20 years are now being mapped in many diverse settings, across LAMIC and developed world settings, paving the way for a more complete understanding of the etiology of psychoses. The methodological challenges of conducting incidence- and outcome-based epidemiology across diverse settings are formidable, and no one single study design will be applicable in all situations. Reassuringly, this session demonstrated that a new wave of researchers are thinking carefully about such issues. It was perhaps Oye Gureje who summarized the challenge ahead best: “The earth is not flat, but full of potholes.” Potholes that he and others are successfully circumnavigating.—James Kirkbride.