Sexual dysfunction is a common problem in people with schizophrenia affecting both treated and untreated patients alike. It affects between 30-80% of women and 45-80% of men. There are a number of possible reasons for this, one of them being the side effects of antipsychotic drugs. Sexual dysfunction is considered to be one of the worst side effects of medication and is a major cause of poor quality of life, a negative attitude to therapy and treatment non-compliance. A review of studies, published since 2002, into the side effects of antipsychotic drugs found that risperidone produced the worst side effects, followed in descending order by haloperidol, olanzapine, quetiapine and aripiprazole.
Baggeley, Martin - Sexual dysfunction in schizophrenia: focus on recent evidence Human Psychopharmacology March 2008, 23(3), 201-209