The project received Ethical Approval by the North East Wales NHS Trust, and the School of Psychology at Bangor University, North Wales, UK. All participants provided written informed consent prior to their inclusion in the study.
Recruitment and participants
Forty-three children (35 boys) between the ages of 4 years 1 month and 11 years (M = 7 years and 3 months, SD = 1 year and 6 months) meeting study criteria for ADHD entered the trial. Children who had been referred to child and adolescent mental health services in North Wales for ADHD and were undergoing ADHD assessments but not yet medicated were invited to participate in the study.