One hundred schizophrenics and 58 patients with an affective psychosis who were in relatively stable condition and were being treated as outpatients, as well as 30 patients receiving dermatological treatment, were questioned in a semistructured interview about their sexual history. Forty-nine percent of schizophrenics, 36.2% of those with affective disorders, and 13.3% of control patients had a sexual dysfunction. The most frequent form experienced by psychiatric patients was hypoactive sexual desire disorder. Underlying causes were presumed to be multifactorial in most cases (expert rating). The patients most frequently affected by sexual dysfunctions were schizophrenics on neuroleptic medication, whereas schizophrenic patients not on any medication had fewer dysfunctions and control patients were only minimally affected. Neither the nature of the psychopharmaceuticals nor the dose level had a specific influence on the frequency of sexual dysfunctions.