To investigate response to Divalproex sodium (DVPX) with respect to Reactive/Affective/Defensive/Impulsive (RADI) and Proactive/Instrumental/Premeditated (PIP) aggression among adolescent males with conduct disorder (CD), using results from a randomized, double-blind, placebo-controlled trial. It was hypothesized that DVPX response among participants with RADI aggression would be greater than among those with PIP aggression. Fifty-eight ethnically diverse males with severe CD were assigned to High Distress (HDCD) or Low Distress (LDCD) Conduct Disorder, corresponding with RADI and PIP aggression, respectively. Following a 1-week washout, all subjects were randomized to a high dose (up to 1,500 mg/day) or low dose (up to 250 mg/day) of DVPX. Baseline and endpoint assessments included Clinical Global Impression (CGI), Achenbach Self Report (YSR), and Weinberger Adjustment Inventory (WAI-62). Response to DVPX was significantly higher in the HDCD group (64%) than in the LDCD group (22%) in the high-dose treatment group (p = 0.03). Mean weekly WAI-62 distress scores declined significantly among the HDCD subjects than among LDCD subjects in the high-dose group. These results support the utility of mood stabilizing agents such as DVPX in treating patients with disorders characterized by the RADI pattern of aggression, including those with severe CD.