Ramezani 2019.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: parallel group
Participants	Substance: opioids Baseline characteristics Mindfulness‐based intervention Number randomized: 16 Control 1 Number randomized: 13 Overall Number randomized: 29 Included criteria: receiving treatment at substance dependence clinic, not attending other treatment Excluded criteria: absence from 2+ therapy sessions, unwillingness to continue treatment, lack of methadone consumption, being illiterate Number missing: not reported Reason missing: not reported Baseline differences: not reported Age: 33.3 Percent female: 0% Race/Ethnicity: 100% Iranian
Interventions	Intervention characteristics Mindfulness‐based intervention Group name: MBCT Theory: Segal et al. (2002) Duration: 5 weeks Timing: 2x week for 2 hours Delivery: unclear Providers: not reported Co‐intervention: methadone Integrity: not reported Compliance: not reported Control 1: no treatment control Co‐intervention: methadone
Outcomes	No eligible outcomes reported
Identification	Sponsorship source: n/a Country: Iran Setting: unclear Authors name: Ramezani Institution: University of Mohaghegh Ardabili Email: lavinramezani@yahoo.com Address: Department of Psychology, Faculty of Education and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran COI: none Diagnosis tool: receiving treatment at substance dependence clinic Diagnosis type: informal Funding: The Deputy of Research and Technology of Kurdistan University of Medical Sciences Journal: Journal of Practice in Clinical Psychology Publication type: published report Secondary publications: none
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No description
Allocation concealment (selection bias)	Unclear risk	No description
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Dropout not reported
Selective reporting (reporting bias)	Unclear risk	No protocol available, no statement of primary outcome
Other bias: equivalence of baseline characteristics (selection bias)	Unclear risk	Not reported