Evaluation of an Interactive Mobile Phone-Based Brief Intervention to Reduce Substance-Impaired Driving

Substance-Impaired Driving among emerging adults remains a significant public health concern and may be the single riskiest substance-related outcome among young adults. Brief Interventions (BIs) have been shown to reduce alcohol-impaired driving among this age group, but are not often implemented - despite their demonstrated efficacy - because it is not economically feasible to deliver in-person BIs to all emerging adult substance users. The present study will be the first to examine whether a text-messaging-based cannabis-impaired driving BI significantly decreases cannabis-impaired driving among emerging adult cannabis users compared to an informational control. Participants will be 149 emerging adults who endorse driving after cannabis use (or combined alcohol and cannabis use) at least three times in the past 3 months. After completing baseline measures, participants will be randomly assigned to receive either: a) substance use information, b) a substance-impaired driving personalized feedback intervention, or c) a substance-impaired driving personalized feedback intervention plus interactive text messages. Participants will complete outcome measures 3 and 6 months post-intervention. Repeated measures mixed modeling analyses will be used to determine whether the intervention significantly reduces substance-impaired driving over time. The project has two specific aims: 1) to evaluate a text based cannabis-impaired driving intervention in a randomized clinical trial, and 2) to determine whether the use of interactive text-messages sustains intervention effects over time.