Calsyn 1994

Methods	Randomised controlled trial with six groups.
Participants	Country: USA. Setting: NA. Health problem: addictions (opiate). Recruitment: health system. Participants: adult patients (n=353).
Interventions	Contract features: Form: written; Parties: patients‐practitioners; Incentives: other; Co‐interventions: yes. Three of the groups (Groups 1 to 3) included contingency contracting ‐ treatment depending on reaching goals for abstinence from illicit drugs. Group 1: Medication only: saw counsellor to complete standard treatment. Group 2: Standard: counselling sessions and optional drug education classes. Group 3: Enhanced: as per Group 2 plus relapse prevention skill training group and weekly group treatment Groups 4, 5 and 6 mirrored the above groups but without the use of contingency contracts.
Outcomes	Rates of illicit drug and alcohol use, discharge rates and length of time to readmission for those discharged.
Notes
Risk of bias
Item	Authors' judgement	Description
Allocation concealment?	Unclear	B ‐ Unclear