The impact of familial loading on gender differences in age at onset of schizophrenia.

To evaluate the impact of familial loading and gender on age at onset, 197 schizophrenic patients were investigated. Patients with familial loading had an earlier age at onset without gender differences. In contrast, an earlier age at onset for men was found in sporadic cases. These data support that both gender and familial loading contribute to the heterogeneity of schizophrenia.