The quality of the study is good. It adequately followed the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) statement, which makes it possible to follow the procedure used by the authors in the study in a transparent manner. In addition, they have carried out a quality assessment of each of the studies following the nine-item Joanna Briggs Institute (JBI Checklist).  

It is a very interesting study, as it includes work from more than 30 years ago (1988-2021), with more than 300,000 children and adolescents included. The results obtained have taken into account data from several countries and concluded that treatment rates are low. 

It is important to note that this study has only combined the most prevalent mental disorders in this age group. In addition, some of the subgroups categorised for analysis include few studies and are very heterogeneous, so caution should be exercised in generalising these results.  

This article confirms what child and adolescent mental health professionals have been saying for years: investment in child and adolescent mental health is insufficient. In my opinion, the increase in the need for psychological and psychiatric care for children and adolescents in recent years is very significant. It seems to me to be a problem of public interest that needs special attention.

The study, which aims to report on treatment rates of mental disorders in children and adolescents, is well-designed and of high quality. The methodology is appropriate and common in current systematic reviews and meta-analyses. The analyses performed are adequate, evidenced the findings highlighted by the authors and represent a contribution to knowledge about mental disorders in childhood and adolescence.  

The results of this meta-analysis, which includes 40 studies, show that the combined treatment rates were 38% for any mental disorder, 36% for depressive disorders, 31% for anxiety disorders, 58% for attention-deficit/hyperactivity disorder, and 49% for behavioural disorders. These results show that treatment rates for mental disorders in children and adolescents were generally low, unsatisfactorily low, especially for depression and anxiety.  

Consequently, treatment rates are lower for internalising versus externalising disorders, as these emotional disorders go more unnoticed in both family and school contexts.

In addition, this study showed that the treatment rate for depressive disorders was higher in adolescents than in children, while the treatment rate for anxiety disorders was higher in children than in adolescents. This result is consistent with a higher prevalence of depression during adolescence**.  

Taking into account the results of the recent meta-analysis by Solmi et al. (2022) which confirmed that 48% of mental disorders start before the age of 18, the results obtained in this study by Wang et al. emphasise the need for early identification of mental disorders in childhood and adolescence, especially anxiety-depressive disorders that go more unnoticed, in order to carry out early interventions. The school setting is an ideal context for the early detection and screening of mental health problems at an early age.  

The results of the study suggest the need to design and implement specific treatments to reduce mental health problems in childhood and adolescence, especially for depression and anxiety, i.e. they suggest the need for specific interventions to improve the current situation identified (low treatment rates).

Therefore, from the results of the study it can also be affirmed that there is now a strong need, firstly, for action in the school context to prevent mental disorders and reduce the stigma of mental disorders and, secondly, to design effective evidence-based clinical treatments for mental disorders in childhood and adolescence.  

Furthermore, in this study, treatment rates for mental disorders in children and adolescents varied significantly across regions and income levels, confirming that the higher the income level of the country, the higher the treatment rate for any mental disorder.  

Therefore, these results suggest the need to invest more in child and adolescent mental health, both to design, implement and validate universal preventive programmes aimed at the general population, primary prevention programmes aimed at strengthening mental health and building resilience, and targeted programmes for at-risk populations and populations with a clear diagnosis, targeting children and adolescents with medium or high levels of symptomatology.

Among the limitations of the study, it should be noted that few studies were selected in this meta-analysis, which leads to biases in relation to both the mental disorders identified and the representativeness of the countries. Specifically, a significantly greater weight of American studies, a few European studies and a single study with a Spanish sample can be observed, which limits the generalisability of the results, which should be taken with caution.

However, the trend in the results on emotional disorders in childhood and adolescence in Spain is not very different from the results obtained in other European countries. In this regard, the latest report on the health outlook for Europe (Health at a Glance: Europe 2022) published in 2022 by the European Commission and the Organisation for Economic Co-operation and Development (OECD, 2022) concludes that with the emergence of covid-19, cases of anxiety and depression have increased significantly in all European Union countries, with Spain occupying second place with the highest percentage of young people with depression. And this points in the same direction as the data from the ANAR Foundation report (ANAR, 2023) which, in addition to confirming that mental health problems have increased significantly, among the reasons for which most consulted in 2022 were: suicide ideation/attempt, self-harm, anxiety, depression and eating disorders.

**Reference cited: Garaigordobil, M., Bernarás, E., y Jaureguizar, J. (2023). Depresión infanto-juvenil: evaluación, prevención y tratamiento. En FOCAD Formación Continuada a Distancia. Edición nº 50. Enero-Marzo. Segunda edición (pp. 1-56). Madrid: Consejo General de la Psicología de España. ISSN: 1989-3906.