AGE-RELATED-CHANGES IN THE ASSOCIATION BETWEEN SEROTONERGIC FUNCTION AND AGGRESSION IN BOYS WITH ADHD

The results of several studies have indicated an inverse relationship between central serotonergic (5-HT) mechanisms and aggression in anima ls and adults, but studies in children have yielded conflicting result s. This study assessed 5-HT function, using a fenfluramine (FEN) chall enge procedure, in an attempt to replicate a previously reported enhan cement of the prolactin (PPL) response to FEN in aggressive relative t o nonaggressive ADHD boys, The study failed to replicate the previous finding. Samples from both studies were then examined to reconcile the discrepant findings. The samples differed significantly in age, The e ntire group (n = 50) was then divided into older and younger subgroups and reanalyzed using a two-way (age-group x aggression) analysis of c ovariance (ANCOVA) controlling for plasma medication level, The ANCOVA generated a significant age-group x aggression interaction. Young agg ressive boys had a significantly greater PRL response to FEN than youn g nonaggressive boys, but no such difference existed in the older age- group, These findings raise the possibility of different developmental trajectories in 5-HT function between aggressive and nonaggressive bo ys. (C) 1997 Society of Biological Psychiatry.