Silverman 2009.

Study characteristics
Methods	Study design: cluster RCT Study grouping: parallel group Allocation concealment: not specified Randomisation method: consumers in 16 sessions were randomised into experimental or control conditions by session. The numbers 1 to 16 were randomised into 2 groups and each group was assigned to a condition. Participants were allocated to the group of the first session they attended.
Participants	Baseline characteristics MT + SC Gender male: 14 (48.27%) Age: 41.00 years Sample size: 29 Verbal therapy + SC Gender male: 15 (40.54%) Age: 40.69 years Sample size: 37 Overall Gender male: 29 (43.93%) Age: 40.85 years Sample size: 66 Inclusion criteria: inpatient on detoxification unit Exclusion criteria: none mentioned Pretreatment: no significant differences between groups in relation to: number of consumers taking part in each session who volunteered to be research participants; total number of consumers in each session; research participants' ages; number of times in rehabilitation/detoxification facility Confirmation of population eligibility (from study author): author confirmed that participants had diagnosis of SUD.
Interventions	Intervention characteristics MT + SC Description: MT group lyric analysis session focusing on relapse prevention and led by a board‐certified music therapist. Therapeutic techniques were manualised using the functional CBT manual provided by Cather and colleagues (2005). Session length: approximately 45 minutes Frequency: single session Duration of treatment: single session Verbal therapy + SC Description: non‐music, scripted verbal therapy group focused on relapse prevention facilitated by the same therapist. Therapeutic techniques were manualised using the functional CBT manual provided by Cather and colleagues (2005). Session length: approximately 45 minutes Frequency: single session Duration of treatment: single session
Outcomes	Motivation for treatment/change – SOCRATES Outcome type: continuous outcome Reporting: partially reported Range: 19–95 Direction: higher is better Data value: endpoint Notes: uses shorter 19‐item version of SOCRATES with 3 factors (taking steps, recognition, and ambivalence) that can contribute to a total score. Data were reported for total score only. Not used: Working alliance (HAQ‐II)
Identification	Sponsorship source: none Country: USA Setting: inpatient detoxification unit Author's name: Michael J Silverman Institution: University of Minnesota Declarations of interest: no conflicts of interest reported
Notes	Email (13 September 2017) from author confirmed that participants met criteria for SUD.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Judgement comment: insufficient information about the sequence generation process to permit judgement.
Allocation concealment (selection bias)	Unclear risk	Judgement comment: insufficient information about allocation concealment to permit judgement.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups. Reasons for missing outcome data unlikely to be related to true outcome.
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 to MT intervention.
Blinding of outcome assessor (detection bias) (subjective outcomes)	Unclear risk	Judgement comment: not possible to blind outcome assessor for self‐report outcomes, though measurement not likely to be influenced differentially between groups.