Introduction

The heterogeneity of schizophrenia has greatly challenged efforts to understand the etiology and pathophysiology of this disorder. Gender has been recognized for a long time as one of a number of factors that may contribute to the heterogeneity of schizophrenia, but only recently have researchers systematically examined the role of gender in the development of schizophrenia and in the modification of its expression. Recent literature reviews of gender differences in schizophrenia found gender differences in various aspects of the schizophrenic syndrome, including age of onset of illness, symptom presentation, course of illness, cognitive performance, neuroradiological abnormalities, and response to antipsychotic medication (Andia & Zisook, 1991; Yassa & Jeste, 1992; Yassa et al., 1991; Tamminga, 1997). A number of other published studies, as well, found gender differences in aspects of the schizophrenic syndrome (Szymanski et al., 1995; Gur et al., 1996; Hafner et al., 1998).

Our own findings suggest that gender accounts for some of the heterogeneity in the varying clinical presentations of schizophrenia; however, the lack of differences on neuropsychological measures suggests that the cognitive deficits seen in schizophrenia are similar in male and female patients (Andia et al., 1995).

Age of onset of schizophrenia

Age of onset of schizophrenia has usually been found to be later in women than in men, regardless of study design, culture, definition of schizophrenia, or definition of age of onset (Loranger, 1984; Castle & Murray, 1993; Hafner et al. 1989, 1998; Angermeyer & Kuhn, 1988; Hambrecht et al., 1992).