Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomized by computer (randomly generated sequences with blocking) to either the treatment or comparison groups.
Allocation concealment (selection bias)	High risk	Neither staff nor participants were blinded to the intervention.
Blinding of participants and personnel (performance bias)	High risk	Blinding of participants and personnel was not possible due to the nature of the intervention and study design.
Blinding of outcome assessment (detection bias)	Unclear risk	No description of blinding of outcomes assessment was provided.
Incomplete outcome data (attrition bias)	High risk	Retention for follow‐up assessments ranged from 82% to 96%. Retention rates in the treatment condition were significantly higher than those in the comparison condition at the 6‐ and 18‐ month follow‐up assessment.
Selective reporting (reporting bias)	Low risk	No evidence of reporting outcomes selectively was detected.
Other bias	Unclear risk	Self‐reported data obtained in this study may be affected by socially desirable responding and recall biases, which were minimized by using A‐CASI for more sensitive questions and a 90‐day recall period rather than a longer period.