A motivational intervention trial to reduce cocaine use

The aim of this study was to test if a motivational intervention would reduce cocaine use. We performed a randomized trial with 6-month follow-up for 198 persons who used cocaine at least weekly. Participants were randomly assigned to a four-session motivational intervention or an assessment control group. We performed an intent-to-treat analysis of past 30-day self-reported cocaine use at 6 months, with those lost to follow-up assumed to use cocaine at their baseline level. Participants were 62% male, 40% Caucasian, and used cocaine an average of 13.8 days over the past month. In the full cohort, there were no significant intervention effects on mean change in cocaine use days (p = .21), past 30-day abstinence (33% vs. 26%, p = .26), or >50% reduction in cocaine use days from baseline (55.7% vs. 46.5%, p = .20). However, among those using cocaine on 15 or more of the 30 days prior to baseline, motivational interviewing participants had a significantly larger mean reduction in cocaine use days (p = .023). There were also no significant group differences in days of employment, quality of life, or substance abuse treatment entry. We conclude that this motivational intervention was more effective than assessment alone at reducing cocaine days among the heaviest community-based users. Both study conditions induced positive effects on cocaine use.