There is now a wealth of evidence, much of it from the IRG, attesting to the fact that a proportion of individuals who later manifest schizophrenia show abnormalities in their early development. For example, Ailsa Russell and colleagues (1997) examined the childhood IQ of individuals who were seen at the Maudsley Children's Department, who then years later (in adult life) were diagnosed as having developed schizophrenia. Their childhood IQ was about 15 points lower than the population average. Since IQ did not fall further after the development of schizophrenia, the investigators provocatively entitled their paper "The Myth of Intellectual Decline in Schizophrenia"; this provoked a heated correspondence.
Mary Cannon and colleagues (1997, 1999) studied all schizophrenic patients who were born in Helsinki, Finland between 1951 and 1960.
This slide shows a class of school children from the largest elementary school in Helsinki in 1960.
Comparison of elementary school records (ages 7-11) for 400 cases and 408 controls revealed no differences in academic performance, but more cases failed to progress as expected to the academic high school system at age 11, and tended to remain on at the elementary schools to complete their education.
The preschizophrenic children also performed significantly worse on subjects involving motor co-ordination (sports and handicrafts). These findings suggest that cognitive and neuromotor impairments may precede adult schizophrenia and are consistent with a neurodevelopmental model. Ongoing work in this sample is examining the relationship between birth complications and later schizophrenia and identifying childhood predictors of symptomatology, outcome, suicidality and violence.
Immigration A series of studies from the IRG and others, have shown a markedly higher rate of schizophrenia in African-Caribbeans resident in the UK compared with their white UK-born counterparts (Bhugra and others, 1997). We have previously shown that this is in the absence of any increased risk to Caribbeans who remain in the West Indies. Of particular interest is that this increased risk is also found in the UK-born offspring of Caribbean migrants, discounting an explanation in terms of migration stress. We have also shown that there is a marked increased risk in the siblings but not the parents of this second generation, which suggests an environmental effect operating particularly upon this second generation.
Initial studies sought to ascertain any evidence of developmental disadvantage such as poor maternal nutrition, poor obstetric care, and possible maternal susceptibility to novel viruses. However, these studies have shown that, if anything, African-Caribbean schizophrenic patients in England have less evidence of obstetric risk than their white counterpart patients (Hutchinson and others, 1997). Current research focuses on the possible role of a paranoid reaction to social disadvantage and discrimination (Gilvarry and others,1997).