Two new studies suggest that psychotic illnesses are related to social factors.  In particular, family breakdown for at least one year before age 16 is linked with a doubling of the risk of adult psychosis.  The studies were conducted by researchers from the Institute of Psychiatry, King’s College, London.

They found schizophrenia was nine times more common in people from African Caribbean origin, and six times more common in people from black African origin than in the white British population.

In a second paper, they found that separation from one or both parents for more than a year before the age of 16, as a consequence of family breakdown, was associated with a 2.5 fold increased risk of developing psychosis in adulthood.

Family breakdown of this type was found to be more common in the African-Caribbean community (31%) than the white community (18%).

Researcher Dr Craig Morgan said: "These findings provide evidence that early social adversity may increase the risk of later psychosis.

"Such early adversity may be one factor contributing to the high rate of psychosis in the African-Caribbean population."

This finding presents a major challenge to the currently accepted view that psychosis results largely, if not entirely, from genetic causes.  More investigation is needed into how social adversity interacts with biological factors.

The researchers also discounted the possibility that drug usage could account for higher psychosis among black people, noting that prevalence of drug abuse is about the same among blacks as among the overall population.

Both papers are to be published in the journal Psychological Medicine and can be downloaded here.

h/t: The Szasz Blog