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

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.