Prolactin response to d-fenfluramine in combat-related post-traumatic stress disorder

Central serotonergic function can be investigated by measuring the prolactin response to the serotonin releasing/uptake agent, d-fenfluramine. This study investigated the effect of diagnosis, depressive symptoms and history of alcohol or tobacco abuse or dependence on the d-fenfluramine test in combat-related post-traumatic stress disorder (PTSD). Male, non-hospitalized combat-exposed veterans diagnosed with PTSD (DSM-III-R) and a similarly aged combat-exposed control group were assessed for both PTSD and depressive symptoms and prolactin responses to a 30-mg d-fenfluramine challenge test. Ninety-five subjects were studied; 23 were controls, 46 subjects met the criteria for current PTSD and 26 for past PTSD. There were no significant differences between the three groups for baseline prolactin, peak prolactin, and time to reach peak, delta prolactin or area under the curve of the prolactin vs. time curve. Depressive symptoms and history of alcohol or tobacco abuse or dependence did not have a confounding effect on the prolactin responses to d-fenfluramine. This study suggests that a blunted prolactin response to d-fenfluramine may be a consequence of combat exposure rather than PTSD. To confirm this, further studies involving both healthy and combat-exposed control groups in addition to subjects with PTSD of similar ages are required.