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 A ttention Deficit Hyperactivity Disorder (ADHD) to determine (1) the utility of this measure as an index of central serotonergic function; and (2) if t he 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, norfenfluram ine (NORFEN). Furthermore, a significant inverse relationship was found bet ween temperature response to FEN and teacher ratings of aggression. Parent ratings of aggression were not significantly correlated with the hypertherm ic response to FEN. Interestingly, the magnitude of the hyperthermic respon se was unrelated to changes in plasma levels of prolactin and cortisol, sug gesting 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 su ggests that decreased central 5-HT is associated with increased aggression.