Prostate cancer and schizophrenia.
OBJECTIVES: To assess the incidence of prostate cancer in individuals with schizophrenia. METHODS: A MEDLINE search was performed for all studies of "prostate cancer" or "cancer" and "schizophrenia." RESULTS: Five studies had age-standardized, site-specific cancer data. All five had a lower standardized incidence ratio for prostate cancer, ranging from 0.49 to 0.76. The incidence of cancer at other sites varied among the studies. Possible explanations included ascertainment bias; genetic factors; antipsychotic drug effects, either by being cancer protective or decreasing testosterone, or both; and lifestyle differences, such as prolonged hospitalization resulting in a decreased opportunity for heterosexual intercourse. CONCLUSIONS: The results of this study have revealed that the incidence of prostate cancer in individuals with schizophrenia is significantly lower than expected.