Does executive function capacity moderate the outcome of executive function training in children with ADHD?

Executive functioning (EF) training interventions aimed at ADHD-symptom reduction have limited results. However, EF training might only be effective for children with relatively poor EF capacity. This randomized double-blind placebo-controlled study examined whether pre-training EF capacity moderates the outcome of an EF-training intervention on measures of near transfer (EF performance) and far transfer (ADHD symptoms and parent-rated EF behavior) immediately after treatment and at 3-month follow-up. Sixty-one children with ADHD (aged 8-12) were randomized either to an EF-training condition where working memory, inhibition and cognitive flexibility were trained, or to a placebo condition. Single moderation models were used. All significant moderation outcomes had small effect sizes. After Bonferroni correction, there were no significant moderators of treatment outcome. Children with poor EF capacity do not benefit more from EF training than from placebo training. Training only EF-impaired children will probably not improve outcomes of EF training studies.