Silverman 2016b.

Study characteristics
Methods	Study design: cluster RCT Study grouping: parallel group Allocation concealment: not specified Randomisation method: consumers in 24 sessions were randomised into experimental or control conditions by session. Thus, each session was assigned to an experimental or control condition consistent with cluster randomisation.
Participants	Baseline characteristics MT + SC Gender male: 33 (55%) Age: 36.58 years Sample size: 60 SC (wait‐list control) Gender male: 46 (55.8%) Age: 36.98 years Sample size: 84 Overall Gender male: 79 (55.2%) Age: 36.78 years Sample size: 144 Inclusion criteria: inpatient on short‐term detoxification unit; able to read and write in English Exclusion criteria: none specified Pretreatment: no significant differences between groups in regard to participants' ages; number of times admitted to a rehabilitation/detoxification facility; number of days on the detoxification unit; gender; ethnic background; drug of choice. Significant between‐group differences in number of patients taking part in each session who volunteered to be research participants and total number of participants in each session (wait‐list control group had greater means than experimental group for both). Confirmation of population eligibility (from study author): author confirmed that participants had diagnosis of SUD.
Interventions	Intervention characteristics MT + SC Description: MT group had lyric analysis sessions with a focus on change and relapse prevention, using scripts to promote standardisation. Session length: 45 minutes Frequency: single session Duration of treatment: single session SC (wait‐list control) Description: wait‐list control Session length: not applicable Frequency: not applicable Duration of treatment: not applicable
Outcomes	Substance craving – BSCS Outcome type: continuous outcome Reporting: partially reported Scale: 5‐point Likert‐type scale for each item Range: 0–12 Direction: lower is better Data value: endpoint Notes: 3 × 5‐point Likert‐type items (total score 12). Higher scores indicate higher levels of craving. Participants completed according to their current craving. Not used: symptoms of withdrawal (Adjective Rating Scale for Withdrawal) Outcome type: continuous outcome Reporting: partially reported Scale: 10‐point Likert‐type scale for each item Range: 0–144 Direction: lower is better Data value: endpoint Notes: higher scores represent worse withdrawal symptoms. 16 items total in this version, total score 144 as per related literature. Completed to express current withdrawal symptoms experienced.
Identification	Sponsorship source: none Country: USA Setting: inpatient detoxification unit Author's name: Michael J Silverman Institution: University of Minnesota Email: silvermj@umn.edu 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. 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.