Comparative studies were eligible for inclusion in the review, and randomised controlled trials (RCTs) and non-randomised controlled studies were included. Studies that focused on parent-involved psychosocial treatment for ADHD were eligible for inclusion, and parents and children could be seen cojointly or separately. Studies that only focused on the treatment of the child, or in which participants received different types of psychosocial intervention, were excluded. The included interventions were cognitive-behavioural interventions, with most interventions relying on group services. The mean duration of treatment was 32 sessions. Studies of ADHD in children (up to 18 years old) were eligible for inclusion, and children were required to be screened for ADHD, either by meeting diagnostic criteria or by scoring in the clinical range on established measures of ADHD symptoms. Most of the studies were reported to focus on school-aged children (no further details provided). No a priori criteria for the outcomes were reported. The outcomes were divided into a number of categories according to the informant involved (child, parent or teacher): child internalising problems, externalising problems, ADHD, social competence, family functioning, self-control and academic performance. Individual outcomes were not reported. Studies were required to report sufficient information to calculate a Cohen's d effect size to be included in the review.
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.