Albornoz 2009.

Study characteristics
Methods	Study design: RCT Study grouping: parallel group Randomisation method: block randomisation using random number lists, completed by statistician Allocation concealment: sequentially numbered envelopes created to ensure allocation concealment
Participants	Baseline characteristics MT + SC Gender male: 12 (100%) Age: 16–60 years Sample size: 12 SC Gender male: 12 (100%) Age: 16–60 years Sample size: 12 Overall Gender male: 24 (100%) Age: 16–60 years Sample size: 24 Inclusion criteria: some type of addiction problem, including addiction or abuse of psychotropic and pharmacological substances, including alcohol; recently admitted to treatment programme for substance abuse at the centre; scores on BDI or HRSD that indicated that they were significantly depressed (i.e. > 10 on BDI, and > 7 on HRSD).  Exclusion criteria: unable to communicate (aphasia); diagnosed with mental retardation and incapable of symbolic thinking; hearing losses that impaired their abilities to hear music or the spoken word; not receiving medication for depression. Pretreatment: no significant difference between groups on pretest BDI (Albornoz 2009, p.35), and no significant differences between groups on pretest HRSD (p.37). Confirmation of population eligibility (from study author): email 9 July 2017: "Participants were diagnosed by psychiatrist/psychologist with the related substance abuse/addiction/dependence diagnoses as per DSM‐IV/ICD‐10".
Interventions	Intervention characteristics MT + SC Description: improvisational MT (instrumental improvisation + discussion) + SC Session length: 2 hours Frequency: once/week Duration of treatment: 3 months SC Description: SC at the facility included: individual psychotherapy, group psychotherapy (emotional and cognitive behavioural groups), family and couple groups, and morning groups conducted by advanced patients, pharmacotherapy, recreational, social and sport activities, special activities, general medical care, and social work assistance Session length: no information Frequency: no information Duration of treatment: 3 months
Outcomes	Self‐report depression (BDI) Outcome type: continuous outcome Reporting: fully reported Range: 0–63 Direction: lower is better Data value: endpoint Notes: raw scores are available for BDI (Albornoz 2009, p.39) Depression – observational report (HRSD) Outcome type: continuous outcome Reporting: fully reported Range: 0–54 Direction: lower is better Data value: endpoint Notes: raw scores are available for HRSD (Albornoz 2009, p.39). Retention in treatment Outcome type: dichotomous outcome Direction: higher is better Data value: endpoint Notes: retention in treatment calculated as the % of participants remaining in treatment at the conclusion of the treatment.
Identification	Sponsorship source: none Country: Venezuela Setting: inpatient and outpatient substance use treatment facility Author's name: Yadira Albornoz Institution: Universidad de los Andes‐Venezuela Email: yadira98@hotmail.com Address: Universidad de los Andes‐Venezuela, Mérida, Venezuela Declarations of interest: no conflicts of interest reported.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Judgement comment: p.24 – random number lists in blocks (generated by statistician).
Allocation concealment (selection bias)	Low risk	Judgement comment: sequentially numbered envelopes were created to ensure allocation concealment.
Blinding of participants and personnel (performance bias) Objective outcomes	Low risk	Judgement comment: not possible to blind participants and providers to MT intervention.
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	Judgement comment: outcome assessor blinded for retention in treatment.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: no missing outcome data.
Selective reporting (reporting bias)	Low risk	Judgement comment: no selective outcome reporting.
Blinding of participants and providers (performance bias) (subjective outcomes)	Low risk	Judgement comment: not possible to blind participants and providers for MT intervention.
Blinding of outcome assessor (detection bias) (subjective outcomes)	Unclear risk	Judgement comment: psychologist completing HRSD was blinded to treatment allocation and participant medical and psychiatric history. Not possible to blind outcome assessor for self‐report outcomes, though measurement not likely to be influenced differentially between groups.