Forty-two studies (3,472 participants) were included in the review comprising 35 randomised controlled trials, five single-sample pre-and post-test designs and two non-randomised studies. The comparator treatments were waiting-list (18 studies), placebo (two studies), and treatment as usual (18 studies).
Interventions compared to waiting-list (18 studies, 1,520 participants): Significant benefits were found with counselling and psychotherapy compared with waiting lists control participants (average d=0.55, 95% CI 0.41 to 0.69; Ι²=0%). At a median follow-up of six months (range one to 12 months follow-up), a small significant effect was found for the continuation of benefit. Significant benefits were also found for the intervention in school-based programmes and in seven clinic-based settings.
Intervention compared to placebo (two studies, 122 participants): There were no significant differences observed between the intervention groups and placebo in these two studies (d=0.01, 95% -0.37 to 0.38; Ι²=0%).
Intervention compared to treatment as usual (18 studies, 1,358 participants): Significant benefits of counselling and psychotherapy were observed compared to treatment as usual (d=0.29, 95% CI 0.16 to 0.43; Ι²=14%). At a median follow-up of nine months (range six to 24 months) in nine studies, significant benefits were observed with interventions compared with treatment as usual. Six studies reported results from school-based treatment with a significant benefit for interventions over treatment as usual.
Five single-sample group designs (62 participants) also showed significant benefits for counselling/psychotherapy in school-age children/adolescents with depression (d=0.36,95% CI 0.17 to 0.54, Ι²=14%).