Iranian Association for Intelligence and Talent Studies International Journal of Education and Cognitive Sciences 3041-8828 7 June 2026 2026 06 01 The Effectiveness of a Multi-Session Motivational Interviewing (MI-Supportive) Intervention Combined with Digital Follow-Up (EMA/SMS) in Reducing Marijuana Use and Enhancing Motivation to Change among Clinical Adolescents: A Randomized Controlled Trial The Effectiveness of a Multi-Session Motivational Interviewing (MI-Supportive) Intervention Combined with Digital Follow-Up (EMA/SMS) in Reducing Marijuana Use and Enhancing Motivation to Change among Clinical Adolescents: A Randomized Controlled Trial 1 13 10.61838/kman.ijecs.317 EN Journal Article 2025 07 03 <p><strong>Purpose: </strong>This study presents a randomized controlled trial examining the effectiveness of a multi‑session Motivational Interviewing (MI‑Supportive) intervention augmented with ecological momentary assessment (EMA) and adaptive SMS follow‑up (MI + EMA/SMS) compared with an active supportive counseling control in reducing marijuana use and enhancing motivation to change among clinical adolescents.</p> <p><strong>Methods and Materials: </strong>Adolescents (N = 240; ages 13–18) referred from outpatient and inpatient adolescent clinical services were randomized 1:1 to receive either four manualized MI sessions (45–60 minutes each) with EMA/SMS digital follow‑up or an active, time‑matched supportive counseling control with non‑adaptive digital contact. Primary outcome was days of cannabis use in the past 30 days assessed via Timeline Followback at baseline, post‑intervention (8 weeks), 3‑month, and 6‑month follow‑up. Secondary outcomes included motivation to change (Readiness Ruler, URICA), cannabis‑related problems (CUDIT‑R), craving, and urine drug screen (UDS) results. EMA captured momentary motivation, craving, and contextual risk, and triggered adaptive SMS messages in the experimental arm. Analyses used intent‑to‑treat mixed‑effects models with multiple imputation for missing data.</p> <p><strong>Findings: </strong>Compared with the active control, the MI + EMA/SMS arm demonstrated greater reductions in days of cannabis use across follow‑up (adjusted mean difference at 6 months = −3.9 days, 95% CI −5.6 to −2.2; Cohen’s d ≈ 0.42, p &lt; .001). Secondary outcomes favored the experimental arm, with larger increases in readiness to change, greater reductions in CUDIT‑R scores, lower proportion of UDS‑positive participants at 6 months (31% vs. 46%), and modest improvements in craving and depressive symptoms. Mediation analyses suggested that increases in EMA‑measured momentary motivation and reductions in craving partially mediated the intervention effect. EMA adherence averaged 72%.</p> <p><strong>Conclusion:</strong> In this trial, integrating multi‑session MI with EMA‑triggered supportive SMS yielded clinically meaningful reductions in adolescent cannabis use and increased motivation to change relative to an active control. These findings support the potential of hybrid, just‑in‑time interventions that combine high‑fidelity psychotherapy with adaptive digital support for adolescent substance use treatment. Future empirical trials are needed to replicate these results, evaluate long‑term durability, and assess cost‑effectiveness and equitable implementation.</p> <p> </p> <p> </p> https://www.journalecs.com/index.php/ecs/article/download/317/295