3.2 Neural Mechanisms of Social Environmental Risk for Schizophrenia

Abstract

Background: Urban birth, urban living, and ethnic minority status are established risk factors for schizophrenia, but the mechanisms are unclear. Previous evidence suggests a causal role of social exposures and adverse experiences, but experimental evidence is scarce. Methods: We combine multimodal neuroimaging with ecological momentary assessment, geolocation and geospatial analysis in an epidemiological longitudinal sample in Germany. Results: We find that established risk factors converge on the perigenual cingulate-amygdala-ventral striatal pathway as shown by structural and functional imaging, supporting a role for the amygdalostriatal system in psychosis risk. Using a combination of PET and fMRI data, we suggest a mechanistic link to psychosis by increased dopamine release and synthesis in striatum secondary to prefrontal dysregulation. Moreover, environmental context, such as greenspace, can mitigate these impacts. Conclusions: This work shows a convergent risk circuit that could guide primary prevention of schizophrenia through reduction of manifestation risk by environmental manipulation.