Objective: To compare clonidine with placebo added to ongoing psychostimulant therapy for the treatment of attention-deficit/hyperactivity disorder with comorbid oppositional defiant disorder or conduct disorder.
Method: Children 6 to 14 years of age recruited through 2000 to 2001 were randomized to receive clonidine syrup 0.10 to 0.20 mg/day (n = 38) or placebo (n = 29) for 6 weeks. Primary outcome measures were the Conduct and Hyperactive Index subscales of the parent-report Conners Behavior Checklist. Side effects were monitored using physiological measures and the Barkley Side Effect Rating Scale.
Results: Evaluable patient analysis showed that significantly more clonidine-treated children than controls were responders on the Conduct scale (21 of 37 versus 6 of 29; chi2(1) = 8.75, p <.01) but not the Hyperactive Index (13 of 37 versus 5 of 29). Compared with placebo, clonidine was associated with a greater reduction in systolic blood pressure measured standing and with transient sedation and dizziness. Clonidine-treated individuals had a greater reduction in a number of unwanted effects associated with psychostimulant treatment compared with placebo.
Conclusions: The findings support the continued use of clonidine in combination with psychostimulant medication to reduce conduct symptoms associated with attention-deficit/hyperactivity disorder. Treatment is well tolerated and unwanted effects are transient.