Prospective and Daily Effects of Cannabis Use on Smoking Outcomes during a Self-Guided Quit Attempt.

INTRODUCTION: Past research suggests that cannabis use is a risk factor for relapse in people trying to quit smoking. Most people attempt to quit smoking without any assistance (i.e., self-guided quitters), yet no one has examined the association between cannabis use and relapse among self-guided quitters. The current study examines how cannabis use might contribute to poorer smoking outcomes in a sample of self-guided quitters. METHODS: Data were taken from a study of unaided smoking cessation in 62 single-smoker couples. Quitters and their Partners completed baseline questionnaires and a 21-day ecological momentary assessment (EMA). This article examines Quitters' and Partners' past-year cannabis use reported at baseline and daily cannabis use during the EMA as predictors of prospective and daily smoking outcomes. RESULTS: We found very little evidence that past-year cannabis use was associated with poorer smoking outcomes. However, Quitters reported greater smoking on days when they or their Partners reported cannabis use. CONCLUSIONS: This study produced evidence to support daily Quitter and Partner cannabis use as a risk factor for poor smoking outcomes. Smoking cessation programs might benefit from targeting cannabis use as well as taking a couples-oriented approach to treatment.