Music therapy is a commonly used intervention added to usual care for psychiatric disorders.

We review the evidence for music therapy and assess its efficacy as an adjunct therapy across psychiatric disorders.

A systematic literature search was conducted in four scientific databases to identify relevant meta-analyses. Articles were assessed with the AMSTAR-2 tool. The results of the high-quality articles were recalculated with the data from the primary studies. We decided to add the results of the lower-rated articles, using a narrative approach. We pooled the primary studies and calculated standardised mean differences (SMD) for the transdiagnostic outcomes of depression, anxiety and quality of life. We used the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) tool to assess the level of evidence.

Meta-analyses were available for autism, dementia, depression, insomnia, schizophrenia and substance use disorders. We identified 40 relevant articles. One article per domain was identified as high quality. Music therapy added to treatment as usual showed therapeutic value in each disorder. The transdiagnostic results showed a positive effect of music therapy on depression (SMD = 0.57, 95% CI 0.36–0.78), anxiety (SMD = 0.47, 95% CI 0.27–0.66) and quality of life (SMD = 0.47, 95% CI 0.24–0.71). However, these effects were not maintained at follow-up, and all results were based on low or very low evidence.

Music therapy shows promising potential as an adjunctive treatment for psychiatric disorders, but methodological weaknesses and variability limit the evidence. More high-quality, well-powered studies are needed to reliably confirm its effect size.