THE ROLE OF MIGRATION IN THE DEVELOPMENT OF PSYCHOTIC DISORDERS: BIOLOGICAL AND PSYCHOLOGICAL CORRELATES.

Severe mental disorders (schizophrenia and bipolar disorder) are major causes of illness worldwide. Despite their large contributions to global burden of disease, the disease mechanisms behind these disorders are still mostly unknown. Recent studies sho w significant similarities in their development, clinical symptomatology and response to treatment. In addition to overlapping genetic risk factors they also share several environmental risk factors. They are now seen as part of the same continuum of ps ychotic disorders and the necessity of studying significant aspects across their diagnostic boundaries are increasingly recognized.Several epidemiological studies and meta-analyses confirm that migration is a significant risk factor in schizophrenia (SCZ) . This risk is increased in both first and second generation immigrants. There are also clear indications of an increased risk of bipolar disorder (BIP) in immigrants. Norway has relatively large immigrant population, and 28% of Oslos inhabitants ar e first- or second generation immigrants. The reason for the increase in risk is not known, but there are several and diverse hypotheses ranging from effects of discrimination to vitamin D deficiencies. In spite of the obvious importance of these finding s both for the understanding of the origin of psychosis and for public help, there is limited research into the mechanisms behind this finding. In addition, different candidate explanations have rarely been studied together in the same sample and even more rarely across the diagnoses of SCZ and BIP. The current project is based in the TOP study groups focus on the longitudinal course of early SCZ and BIP. We have recently investigated the association between perceived discrimination, vitamin D and symptom profiles in a cross sectional study of a mixed first- and multi-episode sample and will follow-up and broaden the study of possible mechanisms behind these effects in a new, longitudinal patient sample