Background: Data from two retrospective first contact studies suggest that the risk of developing very-late onset schizophrenia-like psychosis (SLP) may be raised in older migrant than British-born populations resident in the UK. Objective: To investigate whether the relative excess of SLP observed amongst younger and male migrants in the above studies might have been explained by differences in the age-gender structures of migrant and British-born denominator populations. A secondary aim was to examine the associations of migrant group status and gender with markers of social isolation. Method: Eighty-six new referrals of SLP to the Mile End (1997-2003) and Maudsley (1995-2000) hospitals were identified from two retrospective case note studies. Local census data were used to estimate the denominator populations and to calculate rate ratios for migrant and British-born cases of SLP. Case notes were re-examined, to assess markers of social isolation in migrant and British-born patients. Results: Migrant patients were more likely to be male (odds ratio =4.8; CIodds= 1.8-13.2) than British-born patients. The ratio of first contact rates for migrant compared to British-born populations were highest amongst men. There was a lower mean age of onset of SLP in migrant than British-born patients (t = 4.30, 95% CI = 3.78-10.27), which was largely explained by a higher mean age of illness onset in British-born women. There were no differences between migrant and British-born patients with respect to markers of social isolation. Male patients were more likely to have never married than women (odds ratio = 0.28; 95% CI odds = 0.09-0.89). Conclusion: The age-gender structure of the background population is not sufficient to explain the socio-demographic differences between migrant and British-born patients with SLP. Male patients may be more socially isolated. Copyright © 2005 John Wiley & Sons, Ltd.

Migration risk factors Gender Schizophrenia-like psychosis (SLP) Very-late-onset

schizophrenia demography London correlation analysis human social isolation psychologic assessment sex difference risk assessment psychosis Marital Status Aged Residence Characteristics social status Humans male female Aged, 80 and over Psychotic Disorders risk factor Age of Onset Risk Factors high risk population population research Article Retrospective Studies major clinical study adult Sex Factors United Kingdom data analysis age distribution Emigration and Immigration retrospective study onset age population migration