OBJECTIVES: To explore differences between age subgroups in QOL in atomoxetine treated patients and evaluate correlations between ADHD core symptoms and QOL METHODS: Pooled data of 5 similar clinical atomoxetine trials (8-12 weeks follow-up, 3 placebo-controlled, 2 open-label) were included in the analysis. All studies used the ADHD-RS and the CHIP-CE instruments. Treatment group differences (effect size vs. placebo) in CHIP-CE score changes were compared between different age groups (RESULTS: A total of 611 children (<12yrs) and 183 adolescents (≥12yrs) were included. Baseline CHIP-CE total t-scores (mean±SD; norm: 50±10) were similar in children (29.3±11.58) and adolescents (27.5±12.29) (p=0.296). Greater impairments in the CHIP-CE 'achievement' domain were seen in adolescents than children (t-scores 31.0±10.26 and 28.9±10.71, respectively; p<0.05); there were no clinically relevant differences in other domains. For the CHIP-CE 'risk avoidance' domain, the effect size of atomoxetine was higher in adolescents than in children (0.83, p<0.001 and 0.37, p=0.005; age*treatment interaction p=0.059); age group differences for other domains and CHIP-CE total scores were not clinically relevant. ADHD-RS/CHIP-CE correlations were low at baseline but moderate for change from baseline being similar in age groups. Only the 'risk avoidance' domain showed a trend towards lower correlation of change in adolescents (r=-0.384 and r=-0.545). CONCLUSIONS: Both age groups showed a clinically relevant impairment of QoL at baseline which was similar for adolescents and children in four out of five CHIP-CE domains. In both groups, atomoxetine was effective in improving QoL. For the 'risk avoidance' domain, the effect size of atomoxetine was larger in adolescents than in children, while the ADHD-RS/CHIP-CE correlation was lower in adolescents, indicating a lower association with core symptoms.