A Brief, Affordable, Broad-Access Transdiagnostic Intervention (Project RE-THINK) for Adolescents: Quasi-Experimental Study.

Background: Adolescence is a crucial developmental period characterized by elevated stress and significant mental health challenges, including depression and anxiety. With barriers, such as stigma, accessibility, and cost hindering effective treatment, leveraging school systems for mental health interventions offers a strategic advantage due to their reach and potential for scalability. Objective: This study aimed to investigate the immediate impact of "Project RE-THINK," a single-session, digital thought record intervention delivered in a school setting, on negative cognitions and overall emotional valence among adolescents. Methods: Project RE-THINK helps adolescents to identify, examine, and challenge negative cognitions to improve their mental health, as demonstrated through changes in negative cognition and overall emotional valence. Adolescents (N=1052) in grades 10-12 enrolled in high school during the 2023-2024 school year completed the digital thought record intervention activity. Using a quasi-experimental pre/post design, participants read through an example thought record and completed their own thought record, which involved identifying and describing a recent upsetting situation, answering a series of questions to challenge their negative cognition, and learning and using emotion regulation skills regarding the upsetting situation. Measures of pre- and postintervention overall emotional valence and negative cognition were collected to determine the intervention effect on participants' mental health. Results: Descriptive statistics confirmed that smaller proportions of adolescents endorsed feeling negative emotions, such as anger, shame, anxiety, disgust, guilt, sadness, and fear, after the intervention. Paired samples t tests showed that adolescents experienced a significant reduction in their belief in their negative cognition from pre- to postintervention (t1051=27.71; P<.001; d=0.85, 95% CI 0.78-0.93), which demonstrates that the intervention helped them challenge their negative thoughts about their upsetting situation, as well as significant improvements to their overall emotional valence (t1051=-31.85; P<.001; d=-0.98, 95% CI -1.06 to -0.91), which demonstrates that the intervention helped them feel better about their upsetting situation. Findings also showed a significant correlation between change in negative cognition and change in overall emotional valence (r=0.25; P<.001), supporting our hypothesis that reducing the strength of belief in negative cognitions can help improve one's emotions. Finally, analysis of covariance (ANCOVAs) confirmed that there were no significant differences in intervention efficacy by gender, race and ethnicity, or socioeconomic status, suggesting broad intervention efficacy across adolescents from different backgrounds and experiences. Conclusions: Project RE-THINK effectively improved both cognitive and emotional outcomes among adolescents, demonstrating its potential as a scalable, low-cost intervention within school settings. Future studies should explore the longitudinal effects and potential integration of such interventions into regular school curricula to help adolescents learn effective emotions and coping skills as well as to help protect and sustain adolescent mental health.