Witkiewitz 2014.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: parallel group
Participants	Substance: various substances Baseline characteristics Mindfulness‐based intervention Number randomized: 55 Relapse prevention Number randomized: 50 Overall Number randomized: 105 Included criteria: residency at the treatment center, proficiency in the English language, willingness to be randomized to treatment condition, and sufficient self‐reported cognitive ability to understand and provide consent Excluded criteria: none Number missing: 34 Reason missing: switched groups before starting treatment, opted out of study, left center, failed to respond Baseline differences: none Age: 34.0 Percent female: 100 % Race/Ethnicity: 34.5% to 51.0% white, 10.2% to 12.7% African American, 7.3% to 10.2% Native American, 2% to 3.6% Asian, 0% to 1.8% Hispanic/Latinx
Interventions	Intervention characteristics Mindfulness‐based intervention Group name: Mindfulness‐based relapse prevention Theory: Mindfulness‐based relapse prevention (Bowen et al., 2010) Duration: 8 weeks Timing: Twice per week for 50 minutes Delivery: group Providers: master's level clinician employed by treatment program and trained in MBRP and MBSR Co‐intervention: residential treatment‐as‐usual Integrity: not reported Compliance: not reported Control 1 Group name: Relapse prevention Theory: Daley and Marlatt (2006), Coping Skills Training Guide (Monti et al., 2002) Duration: 8 weeks Timing: twice per week for 50 minutes Delivery: group Providers: master's level clinician employed by treatment center trained in RP Co‐intervention: residential treatment‐as‐usual Integrity: not reported Compliance: not reported
Outcomes	Drug use days Outcome type: continuous outcome Reporting: fully reported Direction: lower is better Data value: endpoint Time point: post‐treatment Treatment acceptability (attrition) Outcome type: dichotomous outcome Reporting: fully reported Direction: lower is better Data value: endpoint Time point: post‐treatment
Identification	Sponsorship source: Washington State University Vancouver grant Country: USA Setting: residential Authors name: Katie Witkiewitz Institution: University of New Mexico Email: katiew@unm.edu Address: Dr Katie Witkiewitz, PhD, Department of Psychology, Center on Alcoholism, Substance Abuse, and Addictions, University of New Mexico, 2650 Yale Blvd SE, Albuquerque, NM, USA COI: none Diagnosis tool: receiving residential treatment Diagnosis type: informal Funding: Washington State University Vancouver grant Journal: Substance Use & Misuse Publication type: published report Secondary publications: none
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Judgement comment: quote: "random number generator"
Allocation concealment (selection bias)	Unclear risk	Judgement comment: not reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: no blinding
Blinding of outcome assessment (detection bias) Treatment acceptability (attrition)	Low risk	Objective measure
Blinding of outcome assessment (detection bias) All non‐attrition outcomes	High risk	Self‐report
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: reasons for dropout and amount of dropout similar across groups
Selective reporting (reporting bias)	Low risk	Judgement comment: no protocol but clear statement of plausible primary outcomes
Other bias: equivalence of baseline characteristics (selection bias)	Low risk	Judgement comment: no baseline differences