Obstetric complications and risk of schizophrenia - Effect of gender, age at diagnosis and maternal history of psychosis

Background Obstetric complications have been studied frequently as possible risk factors for schizophrenia. Aims To test the hypotheses that individual obstetric complications are mos t strongly associated with an increased risk of schizophrenia in males, inp atients with an early age at first diagnosis and in subjects with a materna l history of psychosis. Method Cases of schizophrenia diagnosed between January 1971 and June 1994 were identified in the Stockholm County In-Patient Register. Controls were matched on age, gender, hospital of birth and parish of birth. Obstetric da ta were recorded blind to case-control status for 524 cases and 1043 contro ls. Results This study did not find any large or consistent effect of gender, a ge at diagnosis or maternal history of psychosis on the risk of schizophren ia associated with individual complications. Conclusions Future studies should examine these effects using a much larger sample that includes patients with schizophrenia and control subjects whos e genetic risk of schizophrenia has been assessed accurately. Declaration of interest No conflict of interest. Support from the Swedish M edical Research Council, the Stanley Foundation, the Soderberg - Konigska F oundation and the Torsten and Ragnar Soderberg Foundation.