Sex differences in the aetiology of schizophrenia

Abstract

SummaryThis article deals with aetiological factors which might explain sex differences in incidence, symptoms, premorbid adjustment, and outcome of schizophrenia. Research on stress raises the question of whether gender‐specific stresses are involved in the development of schizophrenia. A loss of and separation from the same sex parent seem to be associated with psychopathology in general and schizophrenia in particular. Studies of marital status and schizophrenia indicate that the single and widowed status may be more stressful for males than females, but these findings are confounded by selective factors.Higher rates of concordance among women (twins, siblings) suggest that genetic factors are more often involved in the development of schizophrenia in women than men. Since studies of concordance rates are based on chronic hospitalized patients, they deal with biased samples. More recent studies which use consecutive admissions do not reveal sex differences in concord‐ ance. However, they indicate tha: there are more women than men among schizophrenics with schizophrenic siblings regardless of their sex; this would suggest that women are more susceptible to family disturbance than men.Prenatal and postnatal organic insults are found more among psychotic and schizophrenic males than females. Pregnancy and birth complications are also associated with the development of schizophrenia in males rather than females. Research on sex differences in brain lateralization suggests that bilateral representation of language and visuo‐spatial function in females may be protective against schizophrenia. Studies of the galvanic skin response and platelet monoamine oxidase activity suggest that physiological and biochemical factors are related to schizophrenia in males more than females. Although sex hormones are not directly implicated as aetiological factors in schizophrenia, evidence reveals that androgens may increase male vulnerability whereas oestrogens may protect the female against an early schizophrenic breakdown.