What Can Hearing Loss Tell Us About Social Defeat, Dopamine Sensitization, and Schizophrenia?

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October 10, 2014. Like people with schizophrenia, those with severe hearing impairment (SHI) show increased dopamine hypersensitivity in the striatum, reports a new study published online October 1 in JAMA Psychiatry. The findings bolster the social defeat hypothesis of schizophrenia, first suggested in 2005 by lead study author Jean-Paul Selten of the Rivierduinen Institute for Mental Health Care, Leiden, the Netherlands.

The hypothesis originated as a parsimonious explanation for why a variety of risk factors, especially migration and childhood trauma, are associated with schizophrenia (see SRF related news report). It states that long-term exposure to social defeat—the negative experience resulting from being excluded from the societal majority—results in a sensitization of the mesolimbic dopamine system that predisposes one to psychosis (Selten et al., 2013).

http://www.schizophreniaforum.org/new/detail.asp?id=2103

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Even within groups of SZ (majority of smokers), a non-smoking individual can experience social defeat and marginalization due to the very importance of tobacco in SZ “micro-society” in psychiatric environment.

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eh @y76 think it mainly talking about children and risk factors. So they can intervene.

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According to the social defeat (SD) hypothesis, published in 2005, long-term exposure to the experience of SD may lead to sensitization of the mesolimbic dopamine (DA) system and thereby increase the risk for schizophrenia. The hypothesis posits that SD (ie, the negative experience of being excluded from the majority group) is the common denominator of 5 major schizophrenia risk factors: urban upbringing, migration, childhood trauma, low intelligence, and drug abuse. The purpose of this update of the literature since 2005 is to answer 2 questions: (1) What is the evidence that SD explains the association between schizophrenia and these risk factors? (2) What is the evidence that SD leads to sensitization of the mesolimbic DA system? The evidence for SD as the mechanism underlying the increased risk was found to be strongest for migration and childhood trauma, while the evidence for urban upbringing, low intelligence, and drug abuse is suggestive, but insufficient. Some other findings that may support the hypothesis are the association between risk for schizophrenia and African American ethnicity, unemployment, single status, hearing impairment, autism, illiteracy, short stature, Klinefelter syndrome, and, possibly, sexual minority status. While the evidence that SD in humans leads to sensitization of the mesolimbic DA system is not sufficient, due to lack of studies, the evidence for this in animals is strong.

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If social pressure is able to produce risk factors linked to social defeat, we can suppose that protection factors may also exist. Neuroendocrinologist Robert Sapolsky unveils that the closer they are to alpha male, the more kenyan baboons are protected from stress metabolites that lessen their health. Of inequality among primates.

Sapolsky article wired.com

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wow…makes sense.