Serotonin Dysfunction in Pathological Gamblers: Increased Prolactin Response to Oral m-CPP Versus Placebo

Abstract

ABSTRACTObjectiveAcute administration of the partial serotonin (5-HT) agonist meta-chlorophenylpi-perazine (m-CPP), that is used also as a street drug, has been reported to induce a “high” and craving response in various impulsive and sub-stance addiction disorders.IntroductionTo clarify altered 5-HT metabolism in pathological gamblers and to explore the specific role of serotonergic system in non substance addictions, we assessed behavioral (“high” and “craving”) and neuroendocrine (prolactin and cortisol) responses to an oral single dose of m-CPP and placebo in pathological gamblers and matched controls. Moreover, the relationship between neuroendocrine outcome and clinical severity has been assessed.MethodTwenty-six pathological gamblers and 26 healthy control subjects enter a double-blind, placebo-controlled-crossed administration of orally dose m-CPP 0.5 mg/kg. Outcome measures included prolactin and cortisol levels, gambling severity, mood, craving and “high” scales.ResultsPathological gamblers had significantly increased prolactin response compared to controls at 180 minutes and at 210 minutes post–administration. Greater pathological gamblers severity correlated with increased neuroendocrine responsiveness to m-CCP, suggesting greater 5-HT dysregulation. Pathological gambling patients had a significantly increased “high” sensation after m-CPP administration compared with control.ConclusionThese results provide additional evidence for 5-HT disturbance in pathological gamblers and they support the hypotheses that the role of the 5-HT dysfunction related to the experience of “high” might represent the path-way that leads to dyscontrolled behavior in patho-logical gamblers. Furthermore, the “high” feeling induced by m-CPP in pathological subjects may represent a marker of vulnerability to both behav-ioral and substance addictions.