Background Drug-related outcomes expectancies and refusal self-efficacy are core components of Social Cognitive Theory. Both predict treatment outcome in alcohol use disorders. Few studies have reported expectancies and refusal self-efficacy in cannabis dependence. None have examined both, although both constructs are key targets in Cognitive-Behavioural Therapy (CBT). This study tests the predictive role of expectancies and refusal self-efficacy in treatment outcome for cannabis dependence. Design Outpatients completed a comprehensive assessment when commencing cannabis treatment and predictors of treatment outcome were tested. Setting A university hospital alcohol and drug outpatient clinic. Participants 221 cannabis-dependent patients participated in a 6-week CBT program where the goal was abstinence. Measurements Cannabis Expectancy Questionnaire and Cannabis Refusal Self-Efficacy Questionnaire, cannabis dependence severity [Severity of Dependence Scale], psychological distress [General Health Questionnaire] at baseline; the timeline follow-back procedure at baseline and each session. Findings Patients reporting lower confidence in their ability to resist cannabis during high negative affect (emotional relief refusal self-efficacy) had a lower likelihood of abstinence (p\ua0=\ua00.004), more days of use (p\ua
