Clinician mindfulness, Motivational Interviewing and treatment outcomes for substance-using adolescents

Adolescent substance use is an increasing public health concern worth attention. Brief interventions for adolescent substance use such as Motivational Interviewing (MI) could be improved. The purpose of this efficacy study was to examine the impact of clinicians' mindfulness practice on their clients' outcomes, through their delivery of MI-based interventions. Clinicians participating in an MI in-school intervention for adolescent substance use were assigned to acquire a personal mindfulness practice or to continue providing treatment as usual. Clinicians who were assigned to the mindfulness group were hypothesized to improve treatment outcomes for their adolescent clients, and this relationship was hypothesized to be mediated by increased adherence to MI. Contrary to study hypotheses, results indicated that clients of clinicians assigned to the mindfulness group reported significantly more substance use-related consequences than the control group. Group assignment did not significantly predict any treatment outcomes. Post-hoc analyses indicated that group assignment was found to predict mindfulness practice, F(1, 43) = 14.708, R2 = 0.631, DeltaF = 42.850, Delta R2 = 0.368, p < 0.001, B = 13.649, and the mindfulness trait, "acting with awareness" (an ability to give undivided attention to one task at a time), F(1, 47) = 6.167, R 2 = 0.116, p = 0.017, B = 0.210. This mindfulness trait, acting with awareness, was found to predict adolescents' treatment outcomes, including post-treatment alcohol use, F(1, 41) = 20.477, R2 = 0.500, DeltaF = 9.308, DeltaR2 = 0.114, p = 0.004, B = -0.198, and marijuana use, F(1, 43) = 12.572, R2 = 0.369, DeltaF = 7.812, Delta R2 = 0.115, p = 0.008, B = -0.649, as well as important components of MI adherence, including the MI summary score, "Reflections to Questions Ratio," which indicates proficient reflective listening, F(1, 35) = 5.894, R 2 = 0.144, p = 0.020, B = 0.032. An additional hypothesis was proposed: proficient reflective listening skills would mediate the relationship between the mindfulness trait, acting with awareness and treatment outcomes. Direct pathways in this model were found to be significant. However, the overall mediation was not supported. Implications and future directions are discussed.