Weaving Causal Explanations of Schizophrenia in Urban Areas: The Role of Gene-Environment Selection.

Abstract

Schizophrenia has long been reported to be more common in urban areas, although recent research suggests this association may not occur in low- and middle-income countries. Explanations of this urbanicity association, entwined with links between the disorder and socioeconomic deprivation, have led people to question the possibilities of a reverse causal association: do people with early illness or strong liability drift into cities and down the social scale, or do those environments exert a toxic effect? Few studies dissect city life from a socioenvironmental context4 but urbanicity certainly is associated with cognition and the brain. Evidence is also emerging that part of the liability to living in deprived neighborhoods is associated with genetics; it is heritable, and, moreover, genes conferring liability to schizophrenia may be particularly involved.