Abstract: We included 10 studies (165 participants) that examined the short- and medium-term effect of music therapy interventions (one week to seven months) for children with ASD. Music therapy was superior to 'placebo' therapy or standard care with respect to the primary outcomes social interaction within the therapy context (SMD 1.06, 95% CI 0.02 to 2.10, 1 RCT, n = 10); generalised social interaction outside of the therapy context (SMD 0.71, 95% CI 0.18 to 1.25, 3 RCTs, n = 57, moderate quality evidence), non-verbal communicative skills within the therapy context (SMD 0.57, 95% CI 0.29 to 0.85, 3 RCTs, n = 30), verbal communicative skills (SMD 0.33, 95% CI 0.16 to 0.49, 6 RCTs, n = 139), initiating behaviour (SMD 0.73, 95% CI 0.36 to 1.11, 3 RCTs, n = 22, moderate quality evidence), and social-emotional reciprocity (SMD 2.28, 95% CI 0.73 to 3.83, 1 RCT, n = 10, low quality evidence). There was no statistically significant difference in non-verbal communicative skills outside of the therapy context (SMD 0.48, 95% CI -0.02 to 0.98, 3 RCTs, n = 57, low quality evidence). Music therapy was also superior to 'placebo' therapy or standard care in secondary outcome areas, including social adaptation (SMD 0.41, 95% CI 0.21 to 0.60, 4 RCTs, n = 26), joy (SMD 0.96, 95% CI 0.04 to 1.88, 1 RCT, n = 10), and quality of parent-child relationships (SMD 0.82, 95% CI 0.13 to 1.52, 2 RCTs, n = 33, moderate quality evidence). None of the included studies reported any adverse effects. The small sample sizes of the studies limit the methodological strength of these findings. The findings of this updated review provide evidence that music therapy may help children with ASD to improve their skills in primary outcome areas that constitute the core of the condition including social interaction, verbal communication, initiating behaviour, and social-emotional reciprocity. Music therapy may also help to enhance non-verbal communication skills within the therapy context. Furthermore, in secondary outcome areas, music therapy may contribute to increasing social adaptation skills in children with ASD and to promoting the quality of parent-child relationships. In contrast to the studies included in an earlier version of this review published in 2006, the new studies included in this update enhanced the applicability of findings to clinical practice. More research using larger samples and generalised outcome measures is needed to corroborate these findings and to examine whether the effects of music therapy are enduring. When applying the results of this review to practice, it is important to note that the application of music therapy requires specialised academic and clinical training.

Plain-language summary: We included 10 studies with a total number of 165 participants. The studies examined the short- and medium-term effect of music therapy interventions (one week to seven months) for children with ASD. Music therapy was superior to 'placebo' therapy or standard care with respect to social interaction, non-verbal and verbal communicative skills, initiating behaviour, and social-emotional reciprocity. Music therapy was also superior to 'placebo' therapy or standard care in the areas of social adaptation, joy, and the quality of parent-child relationships. None of the included studies reported any side effects caused by music therapy. The quality of the evidence was moderate for social interaction outside of the therapy context, initiating behaviour, social adaptation, and the quality of the parent-child relationship, and low for the other three main outcomes (nonverbal communicative skills outside of the therapy context, verbal communicative skills outside of the therapy context, and social-emotional reciprocity). Reasons for limited quality of the evidence were issues with study design and small number of patients who participated in the studies. Music therapy may help children with ASD to improve their skills in important areas such as social interaction and communication. Music therapy may also contribute to increasing social adaptation skills in children with ASD and to promoting the quality of parent-child relationships. Some of the included studies featured interventions that correspond well with treatment in clinical practice. More research with adequate design and using larger numbers of patients is needed. It is important to specifically examine how long the effects of music therapy last. The application of music therapy requires specialised academic and clinical training. This is important when applying the results of this review to practice.