Asl 2014b.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: parallel group
Participants	Substance: opioids Baseline characteristics Mindfulness‐based intervention Number randomized: 28 Control 1 Number randomized: 25 Overall Number randomized: 53 Included criteria: receiving treatment, BDI‐II score ≥ 14 Excluded criteria: none Number missing: 4 Reason missing: did not continue Baseline differences: no differences on SF‐36 Age: 36.8 Percent female: 0% Race/Ethnicity: 100% Iranian
Interventions	Intervention characteristics Mindfulness‐based intervention Group name: MBSR Theory: Kabat‐Zinn (1990) Duration: 8 weeks Timing: 1x week for 1.5 hours Delivery: group Providers: not reported Co‐intervention: methadone therapy Integrity: not reported Compliance: not reported Control 1: No treatment control Co‐intervention: methadone therapy
Outcomes	Treatment acceptability (attrition) Outcome type: dichotomous outcome Reporting: fully reported Direction: lower is better Data value: endpoint Time point: post‐treatment
Identification	Sponsorship source: Addiction Treatment Clinic of Milad Country: Iran Setting: unclear Authors name: Navid Reza Hosseinzadeh Asl Institution: Hacettepe University Email: navidrha@yahoo.com Address: Institute of Social Sciences, Hacettepe University, Ankara, Turkey COI: not reported Diagnosis tool: receiving treatment through addiction treatment center Diagnosis type: informal Funding: Addiction Treatment Clinic of Milad Journal: Iranian Red Crescent Medical Journal Publication type: published report Secondary publications: none
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding
Blinding of outcome assessment (detection bias) Treatment acceptability (attrition)	Low risk	Objective measure
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Judgement comment: it appears there was no dropout, although not explicitly stated
Selective reporting (reporting bias)	Unclear risk	Judgement comment: no protocol available, no statement of primary outcome
Other bias: equivalence of baseline characteristics (selection bias)	Low risk	Judgement comment: no baseline differences on SF‐36 (p. 2)