New research into higher rates of psychoses

Researchers from the Institute of Psychiatry at King's College London have found higher rates of schizophrenia and other psychoses in certain ethnic minority groups and that parental separation in childhood is associated with an increased risk of developing later psychosis.

These findings, published in Psychological Medicine this month, provide new scientific evidence into these disorders as well as social risk factors. This research forms part of the largest ever study of the development of psychoses in the UK.

Research scientists from south-east London, Nottingham and Bristol have been collaborating in this multi-centre Medical Research Council (MRC) funded AESOP study (Aetiology and Ethnicity of Schizophrenia and Other Psychoses) begun in 1997. The MRC has just announced its intention to provide continuing funding for this unique study over the next five years.

In the first paper researchers found that African Caribbean and Black African populations in England suffer from remarkably high rates of schizophrenia and manic psychosis. For example, schizophrenia was nine times more common in African Caribbeans and six times more common in Black Africans than in the White British population. These high rates were found in both men and women and across all ages, from 16 to 64. Other ethnic minority groups had more modestly increased rates, including non-British Whites who had a 2.5 fold increased risk for schizophrenia.

Dr Paul Fearon, Senior Lecturer at the Institute of Psychiatry and lead author on the paper, explains: 'Although all ethnic minority groups have a greater risk of schizophrenia and other psychoses, our study found that African-Caribbean and Black African communities in England appear to be at particularly high risk, regardless of age or gender. If we can understand and explain these phenomena, we can not only plan better services for these groups, but we may also more fully understand the underlying causes of these disorders.'

The second paper looks at the possible causes of these high rates. The researchers found that separation from one or both parents for more than one 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. Separation from one or both parents was more common in the African-Caribbean community sample (31 per cent) than in the White British community sample (18 per cent).

Taken together, these findings suggest that early social adversity, associated with family breakdown, a) increases the risk of adult psychosis in general and b) contributes to the high rates of psychosis in the African-Caribbean population because it is more common in that population.

Dr Craig Morgan, MRC Research Fellow and Lecturer at the Institute of Psychiatry, and first author on the second paper added: '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. However, while these findings are an important step forward, further research is now needed to more fully understand how specific types of early social adversity interact with psychological and biological factors to cause psychosis.'

Source: King's College London