Is it necessary to distinguish between first and second generation African-Caribbean populaton in psychiatric research?

In attempting to identify factors responsible for the onset, course and prognosis of an illness, it is necessary to identify differences between generations in order to separate the effects of heritability and environment. Ethnicity and culture can also be examined in this way so that changes in culture occasioned by changes in environment can be assessed in terms of their impact on illness. In our work on the family history of psychoses among the African-Caribbean population in Britain we have found that for schrizophrenia, the relatives of first generation (those born in the Caribbean) and white psychotic patients share similiar risks while the risk is markedly increase in the relatives, particularly siblings of the second generation (those born in Britain to Caribbean parents) psychotic patients. For affective psychoses, we have found that the risk in the relatives of the first generation patients is significantly less than for both the white and the second generation relatives. These differences would have been much less noticeable if the separation between first and second generation patients had not been undertaken and would have been more difficult to interpret. Our findings do suggest that there are factors acting on the second generation making them more susceptible than their first generation counterparts to psychotic illness. This therefore diminishes the likelihood that the increased risk of illness in the second generation is due to a genetic effect and is much more likely to be mediated by some selective environmental effects acting either specifically on those families already afflicted by the disease or more generally on the entire second generation population.(AU)

The prevalence of schizophrenia and affective disease in Jamaica - Abstract

This study sought to establish the period of prevalence of schizophrenia and the affective disorders in Jamaica. Data were collected in a National Mental Health Case Register from the Community Mental Health Service, the Bellevue Mental Hospital and the University Hospital of the West Indies. Data from patients seen in the year 1992 with the diagnoses of schizophrenia, manic-depressive psychosis and depression were examined. The prevalence rates for these conditions were established on the basis of total population data for that year. The period prevalence rate for schizophrenia was found to be 2.1 per 1000, for manic-depressive psychosis 0.16 per 1000, and for depression 0.61 per 1000. The age-corrected (15ñ) prevalence rates were 3.1 per 1000, 0.23 per 1000 and 0.88 per 1000, resptively. There was a significant male preponderance for schizophrenia (p=0.02) and a female preponderance for depression (p = 0.0000001). The present findings for the prevalence rate of schizophrenis are more in keeping with those studies which suggest a unitary prevalence of this condiiton worldwide (AU)

Psychiatric hospital admission rates in Jamaica, 1971 and 1988

The overall psychiatric hospital admission rates in Jamaica were 136 per 100,000 in 1971 and 69 per 100,000 in 1988. The admission rate for schizophrenia was 69 per 100,000 in 1971 and 35 per 100,000 in 1988. The 49 percent reduction in admission rates over these 17 years is attributed to the introduction of an island-wide community mental health service with psychiatric admission to general parish hospitals in 1972. This admission rate for schizophrenia is five to six times lower than the rate reported for Afro-Caribbeans in the UK by a number of studies, and is more in keeping with the admission rate for schizophrenia reported for the general population in England. (AU)