Computer-Based Motivational Interviews for Cannabis Showed Promise but Were Less Effective Than Face-to-Face

Both interview formats generated similar amounts of change talk and sustain talk after adjusting for verbosity. However, the relationship between change talk and actual behavior change differed by format: in face-to-face interviews, stronger change talk trended toward reduced marijuana use at 2 months (though not significant, p=0.08), while in the computer format, change talk did not predict behavior change.

Randomized controlled trial with 150 marijuana users and ambivalent non-users assigned to face-to-face or computer-mediated motivational-type interviews. Change talk was coded using Amrhein's manual. Marijuana use was assessed at 2-month follow-up.

Scaling up motivational interviewing through computer platforms could reach more cannabis users. This study suggests the format shows promise for generating the right kind of conversation, but translating that into behavior change may require the human connection of face-to-face interaction.

Digital health interventions for substance use are expanding rapidly. This study provides important nuance: computers can facilitate meaningful therapeutic conversations, but the mechanism by which those conversations change behavior may require elements unique to human interaction.

Small sample size (150) spread across user types. Two-month follow-up is short. Self-reported marijuana use. The motivational interview format was adapted, not standard MI. Computer-mediated format may improve with technological advances.