Peer Review Report For: Mental health interventions targeting children and young people: A mapping review of interventions, follow-up, and evidence gaps [version 2; peer review: 2 approved, 1 approved with reservations]

Background Young people with mental disorders should be offered evidence-based treatments. In 2018, we developed a national evidence portal in Norway providing access to living evidence summaries. This work has been an important contribution to mental health care in Norway but is also a rich data source for exploring the existing research. At the time of this study, eight overviews of overviews (OoO) were published addressing the effects of treatments for attention deficit / hyperactivity disorder (ADHD), anxiety, depression, bipolar disorder, psychosis, obsessive compulsive disorder, self-harm and trauma / post-traumatic stress disorder. The objective of this study was to do a secondary analysis of this evidence to describe the state-of-the art in this field, and to map: treatments evaluated for each diagnostic group and the longest time of follow-up treatment comparisons evaluated for more than one diagnostic group Methods We performed a mapping review. Data extraction was performed independently by two authors. All data was entered into Excel. Unique treatment comparisons were visualised in Sunburst diagrams. The longest time of follow-up and treatments evaluated across diagnostic groups were reported in descriptive tables. Results We identified 200 treatment comparisons including a wide variety of interventions. Some diagnoses are treated mostly with pharmaceutical therapies (such as bipolar disorder) or psychological therapy alone or in combination (such as anxiety and psychosis). Others are treated with a broader spectrum of therapeutic approaches (such as depression and ADHD). The evidence supporting most treatments is of low to very low certainty. Ten percent of the comparisons included follow-up assessments beyond 12 months. Cognitive behavioural therapy, dialectic behavioural therapy, physical activity and mindfulness interventions were effective across populations. Conclusions The evidence supporting treatment of mental disorders in young people has important limitations. Future research efforts should address these evidence gaps.