Abstract: Ten new studies have been added to this update; 18 studies with a total 1215 participants are now included. These examined effects of music therapy over the short, medium, and long-term, with treatment dosage varying from seven to 240 sessions. Overall, most information is from studies at low or unclear risk of bias A positive effect on global state was found for music therapy compared to standard care (medium term, 2 RCTs, n = 133, RR 0.38 95% confidence interval (CI) 0.24 to 0.59, low-quality evidence, number needed to treat for an additional beneficial outcome NNTB 2, 95% CI 2 to 4). No binary data were available for other outcomes. Medium-term continuous data identified good effects for music therapy on negative symptoms using the Scale for the Assessment of Negative Symptoms (3 RCTs, n = 177, SMD - 0.55 95% CI -0.87 to -0.24, low-quality evidence). General mental state endpoint scores on the Positive and Negative Symptoms Scale were better for music therapy (2 RCTs, n = 159, SMD -0.97 95% CI -1.31 to -0.63, low-quality evidence), as were average endpoint scores on the Brief Psychiatric Rating Scale (1 RCT, n = 70, SMD -1.25 95% CI -1.77 to -0.73, moderate-quality evidence). Medium-term average endpoint scores using the Global Assessment of Functioning showed no effect for music therapy on general functioning (2 RCTs, n = 118, SMD -0.19 CI -0.56 to 0.18, moderate-quality evidence). However, positive effects for music therapy were found for both social functioning (Social Disability Screening Schedule scores; 2 RCTs, n = 160, SMD -0.72 95% CI -1.04 to -0.40), and quality of life (General Well-Being Schedule scores: 1 RCT, n = 72, SMD 1.82 95% CI 1.27 to 2.38, moderate-quality evidence). There were no data available for adverse effects, service use, engagement with services, or cost. Moderate- to low-quality evidence suggests that music therapy as an addition to standard care improves the global state, mental state (including negative and general symptoms), social functioning, and quality of life of people with schizophrenia or schizophrenia-like disorders. However, effects were inconsistent across studies and depended on the number of music therapy sessions as well as the quality of the music therapy provided. Further research should especially address the long-term effects of music therapy, dose-response relationships, as well as the relevance of outcome measures in relation to music therapy.

Plain-language summary: We ran electronic searches up to January 2015 for trials randomising people with schizophrenia or schizophrenia-like disorders to receive music therapy or standard care. We found and checked 176 potential studies. Eighteen trials with a total of 1215 participants met the review requirements and provided useful data. The evidence currently available is of low to moderate quality. The results of these studies suggest that music therapy improves global state and may also improve mental state, functioning, and quality of life if a sufficient number of music therapy sessions are provided. Music therapy seems to help people with schizophrenia but further research is needed to confirm the positive effects found in this review. This research should especially address the long-term effects of music therapy, the quality of music therapy provided and measure outcomes relevant to music therapy.