A Pilot Study to Determine a Prolactin Threshold that Identifies Improved Sexual Functioning when Switching from a Prolactin-Elevating to a ProlactinNeutral AntipsychoticAuthor(s): Matthew J. Byerly , Paul A. Nakonezny
This pilot study, among men with schizophrenia or schizoaffective disorder who had antipsychotic-associated sexual dysfunction (while taking an antipsychotic with prolactin-elevating effects), examined if there is an antipsychoticassociated prolactin threshold that identified patients who experienced improvement in sexual functioning when switched to an antipsychotic with neutral effects on prolactin levels (quetiapine). Twenty male patients, who were experiencing risperidone-associated sexual dysfunction, were switched to six weeks of either double-blind (n=10) or open-label (n=10) quetiapine (mean dose=295.0 mg/day) treatment. Baseline prolactin levels were obtained. The Arizona Sexual Experience Scale (ASEX) was used to assess sexual functioning. The optimal antipsychoticassociated prolactin threshold that best identified improvement in sexual functioning (defined as ≥20% reduction in ASEX total scores) was determined with a Receiver Operating Characteristic (ROC) analysis and Odds Ratios. A prolactin threshold of ≥17 ng/mL, with 75% sensitivity and 75% specificity, best identified male patients who experienced improvement in sexual functioning when switched to an antipsychotic with neutral prolactin effects (quetiapine). The odds of responding to quetiapine switch were nine times higher in patients with a prolactin level of ≥17 ng/mL versus <17 ng/mL (p<.03). Among male outpatients with schizophrenia or schizoaffective disorder, who experience antipsychotic-associated sexual dysfunction (while taking an antipsychotic with prolactin-elevating effects), this pilot study suggests that prolactin levels of ≥17 ng/mL may identify male patients likely to experience improved sexual functioning when switched to an antipsychotic with neutral prolactin effects.