This review examines the contribution of social exclusion to the pathogenesis of psychosis and its compatibility with the dopamine and/or neurodevelopmental hypotheses. According to the authors, social exclusion is experienced as defeating by humans. In animal studies using the resident-intruder paradigm as a model for defeat, defeated animals show evidence of increased sensitivity to amphetamine, increased dopamine release in the nucleus accumbens and prefrontal cortex, and increased firing of dopaminergic neurons in the ventral tegmental area. For humans, amphetamine-induced striatal dopamine release was significantly greater among nonpsychotic young adults with severe hearing impairment than among normal hearing controls. Other studies reported an association between childhood trauma and increased dopamine function in striatal subregions.
In conclusion, the authors state that “the answer to the question as to whether there are plausible mechanisms whereby social exclusion can contribute to the pathogenesis of psychosis is cautiously affirmative”.
Selten JP, Booij J, Buwalda B and Meyer-Lindenberg A: Biological Mechanisms Whereby Social Exclusion May Contribute to the Etiology of Psychosis: A Narrative Review. Schizophrenia Bulletin [Epub ahead of print, Jan.3, 2017].