The influence of prolactin response to d-fenfluramine on executive functioning in major depression

Background: The main purpose of this study was to assess the influence of serotonergic activity, as measured by prolactin response to d-fenfluramine, on executive functioning in major depression. Methods: Forty-one persons between 22 and 71 years of age who met the DSM-IV criteria for major depressive episode were administered the Wisconsin Card Sorting Test (WCST) in computerized format, and d-fenfluramine was administered orally. Postfenfluramine blood samples for ascertaining plasma prolactin levels were obtained. Results: The key finding was that prolactin response was positively related to four out of five selected WCST variables. Also, increasing age was associated with decreasing WCST performance. There was no interaction between prolactin response and age, indicating that the effects of prolactin response on the WCST generalized across the age range examined. Conclusions: The overall pattern of results suggests that there may be a relationship between serotonergic activity and executive functioning in major depression.