Thermal response to serotonergic challenge and aggression in attention deficit hyperactivity disorder children

Body temperature change in response to the serotonergic (5-HT) enhancer, d,l-fenfluramine (FEN), was examined in 27 prepubescent boys diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) to determine (1) the utility of this measure as an index of central serotonergic function; and (2) if the magnitude of temperature change is associated with aggression. FEN, 1 mg/kg, produced a significant increase in body temperature, the magnitude of which was correlated with plasma levels of the FEN metabolite, norfenfluramine (NORFEN). Furthermore, a significant inverse relationship was found between temperature response to FEN and teacher ratings of aggression. Parent ratings of aggression were not significantly correlated with the hyperthermic response to FEN. Interestingly, the magnitude of the hyperthermic response was unrelated to changes in plasma levels of prolactin and cortisol, suggesting that thermal and neuroendocrine responses are mediated by distinct 5-HT mechanisms. The agreement of these finding with those of studies using other procedures to assess the relationship between 5-HT and aggression suggests that decreased central 5-HT is associated with increased aggression.