A total of 208 patients completed the study, which was terminated early because recruitment had ceased. At 12 months, there was no significant difference between the psychoeducation and control groups in the proportion of patients who discontinued pharmacologic treatment (13.2% versus 14.3%, respectively; size effect −0.3, P=0.34; hazard ratio 0.72, 95% confidence interval 0.36–1.43). Psychoeducation was associated with a significantly greater improvement in ADHD symptoms but not in functional outcome. Parental satisfaction with psychoeducation was high, and satisfaction with pharmacologic treatment was significantly greater in the psychoeducation group. There were no safety concerns.