Comparison 2. Music therapy plus standard care versus active intervention plus standard care.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
2.1 Psychological outcomes (depression self‐report; BDI; high = poor)	1	110	Mean Difference (IV, Random, 95% CI)	‐1.49 [‐4.98, 2.00]
2.1.1 Immediately after end of intervention (1‐day interventions, e.g. detox)	1	110	Mean Difference (IV, Random, 95% CI)	‐1.49 [‐4.98, 2.00]
2.2 Psychological outcomes short‐term follow‐up (depression self‐report; Likert; high = poor)	1	54	Mean Difference (IV, Random, 95% CI)	0.03 [‐1.05, 1.11]
2.2.1 Short‐term follow‐up (1 month after treatment)	1	54	Mean Difference (IV, Random, 95% CI)	0.03 [‐1.05, 1.11]
2.3 Substance craving (various scales, high = poor)	3	232	Std. Mean Difference (IV, Random, 95% CI)	‐0.04 [‐0.56, 0.48]
2.3.1 Immediately after end of intervention (1‐day interventions, e.g. detox)	2	196	Std. Mean Difference (IV, Random, 95% CI)	‐0.27 [‐0.57, 0.03]
2.3.2 Immediately after end of intervention (longer‐term interventions, e.g. rehab: approximately 1–3 months)	1	36	Std. Mean Difference (IV, Random, 95% CI)	0.64 [‐0.03, 1.31]
2.4 Motivation for treatment/change (various tools; RTCQ‐TV, SOCRATES, URICA; higher = good)	5	411	Std. Mean Difference (IV, Random, 95% CI)	0.46 [‐0.00, 0.93]
2.4.1 Immediately after end of intervention (1‐day interventions, e.g. detox)	5	411	Std. Mean Difference (IV, Random, 95% CI)	0.46 [‐0.00, 0.93]
2.5 Motivation to stay sober/clean (Likert, high = good)	3	258	Mean Difference (IV, Random, 95% CI)	0.34 [‐0.11, 0.78]
2.5.1 Immediately after end of intervention (1‐day interventions, e.g. detox)	3	258	Mean Difference (IV, Random, 95% CI)	0.34 [‐0.11, 0.78]
2.6 Substance use short‐term follow‐up (self‐report)	1	140	Risk Ratio (IV, Random, 95% CI)	1.05 [0.85, 1.29]
2.6.1 Short‐term follow‐up (1‐month post‐discharge)	1	140	Risk Ratio (IV, Random, 95% CI)	1.05 [0.85, 1.29]