Schizophrenia Research Blog

Different sexual side effects of antipsychotics?

Antipsychotic treatment and sexual functioning in first-time neuroleptic-treated schizophrenic patients

István Bitter, Bruce R. Basson and Martin R. Dossenbach

International Clinical Psychopharmacology 2005, 20:19–21

This small study attempts to determine if particular antipsychotic medications have a more significant impact on sexual functioning. Sexual function is important and a decrease in function can be a reason for discontinuing medication. The authors were particularly interested in understanding the experience of people who were new to antipsychotic medication. They started by asking a simple questionnaire to patients to see what their level of sexual functioning was like before they started medication. They then followed the patients for six months and assessed their sexual functioning at months 3 and 6. They did this by using clinical ratings and by again asking patients for their rating.

The authors found that many patients with schizophrenia (up to 20% of their sample) have a baseline dysfunction sexually. This may be a decreased libido or other forms of sexual dysfunction. However, the numbers mostly stayed the same as patients began antipsychotic treatment. They found a small difference between patients taking risperidone and olanzapine and that olanzapine patients had a slightly better outcome. One might hypothesize that a reason that risperidone and some of the first generation antipsychotics might have a worse effect on sexual functioning could be related to the sometimes seen side effect of an increased prolactin level. Prolactin is a hormone in the blood that helps to produce milk and is involved in breast development. However, increased prolactin can lead to a decrease in libido when it is not needed.

The difference was very small and there were several methodological compromises made in this study that make the result even less impressive. First, the study was sponsored by the manufacturer of olanzapine and the raters generally worked for the company. Additionally, there was no randomization, control group for comparison and the raters were not blinded to treatment condition as they were the primary psychiatrists for the patients. This further leads to possible bias in the ratings.

Overall, sexual function is important consideration in the treatment of any patient, including those with psychiatric illness. Sexual dysfunction is one of the leading causes of treatment nonadherance and can lead to other morbidities as a result. However, this study does not demonstrate a significant negative effect sexually with second generation antipsychotics. Further research, including more rigorous studies, could help to demonstrate a more meaningful difference clinically and one that might prompt a change of medication if indicated. However, this study does not provide such evidence, though the concept is interesting.

Conflict of interest: B.R. Basson and Martin R. Dossenbach are employees and shareholders of Eli Lilly and Company. Eli Lilly and Company funded the study
István Bitter was an employee of Eli Lilly and Company between November 2000 and August 2003. Olanzapine is made by Eli Lilly and Company.

Click here for the abstract on PubMed

Posted by Jacob at December 21, 2004 11:50 PM | TrackBack