Sex difference in cognitive response to antipsychotic treatment in first episode schizophrenia.

We extend the investigation of cognitive sex differences in schizophrenia in a novel way by grouping cognitive tests according to the direction of the typical sex difference, an approach used in studies of hormonal effects on behavior in other clinical conditions. Additionally, we explore how performance on these 'male' and 'female' tests changed following antipsychotic treatment. Seventy patients with a first hospitalization for schizophrenia or schizophreniform disorder completed cognitive tests before antipsychotic treatment and approximately 5 weeks after treatment. Thirty-nine healthy comparison subjects completed the tests at similar intervals. Primary outcome variables were composite scores on cognitive tests that in normative studies favor males over females ('male' tests) or favor females over males ('female tests'). Overall, patients performed more poorly than healthy individuals. The expected pattern of sex differences was found on the composite test scores, with an advantage for females on 'female' tests and an advantage for males on 'male' tests. Female patients showed a greater improvement on 'female' tests and a decrease in performance on 'male' tests following treatment. Although male patients did not perform significantly better after treatment on 'female' tests, they did improve on non-motor 'male' tests of visuospatial skills. Future studies of the neurocognitive effects of antipsychotic treatment may need to take potential sex differences in cognitive response into account.