The Marijuana Check-up: promoting change in ambivalent marijuana users

Abstract

Aims: To evaluate the efficacy of a two-session assessment and feedback intervention designed to reach and increase motivation for change in marijuana users who were experiencing negative consequences but were ambivalent about change.

Design: Random assignment to one of two types of feedback conditions or a delayed feedback control (DFC) with follow-up assessments at 7 weeks, 6 months and 12 months. Setting University of Washington research center in Seattle, Washington.

Participants: A total of 188 adult male and female marijuana users who responded to advertisements. Interventions A personalized feedback (PF) condition utilizing motivational interviewing was compared to an educational control condition labeled multi-media feedback (MMF).

Measurements: Marijuana use, dependence symptoms, other associated negative consequences and motivational constructs were assessed at all time-points.

Findings: PF participants reported fewer days of use per week, fewer periods of use per day and fewer dependence symptoms at 7 weeks than those in the MMF and DFC conditions. PF participants also reported fewer days of use per week compared to MMF participants at the 12-month follow-up and fewer dependence symptoms at both the 6- and 12-month follow-ups compared to MMF participants.

Conclusions: The PF intervention, delivered in the context of a check-up, shows potential as a way of reaching and motivating change in marijuana users with a diagnosable disorder who otherwise are not ready to approach treatment. Ways of augmenting the modest absolute levels of change are discussed.