Effects of a Digital Parent-Child Single-Session Growth Mindset Intervention on Adolescent Depression and Anxiety Symptoms: A 3-Arm Waitlist Randomized Controlled Trial (Preprint)

<sec> <title>BACKGROUND</title> Depression and anxiety are prevalent among adolescents globally. Parents are the most direct and crucial pillars in supporting adolescents’ mental health, and parental mindsets matter. Yet digital parent-child mindset interventions are rare and understudied. Given promising results from single-session interventions for youth, this study developed and evaluated a parent and child single-session intervention on mindsets of intelligence, failure, and emotion (PC-SMILE) to alleviate adolescent depression and anxiety. </sec> <sec> <title>OBJECTIVE</title> This study aimed to examine the effectiveness of PC-SMILE in reducing depression and anxiety symptoms among adolescents, compared to the child single-session intervention on mindsets of intelligence, failure, and emotion (C-SMILE) and waitlist control groups. </sec> <sec> <title>METHODS</title> Classes from each secondary school were randomized to one of three intervention conditions: PC-SMILE, C-SMILE, or waitlist control. Each intervention took approximately 45 minutes online, which included parent-version and child-version. Both parents and students in the PC-SMILE group received the intervention. For the C-SMILE group, only students received the intervention. Students in the three groups were assessed at 3 time points: baseline before intervention, 2 weeks post-intervention, and 3 months post-intervention, while parents were assessed in baseline and 3-month follow-up. Generalized estimating equations were used to test the effectiveness of the single-session interventions. </sec> <sec> <title>RESULTS</title> A total of 390 parent-child dyads from 7 secondary schools were randomly assigned to either the PC-SMILE intervention group (n = 126), the C-SMILE intervention group (n = 138), or the waitlist control group (n = 126). The intent-to-treat analysis found no significant time*group interaction effects on all outcome measures. However, the results revealed a significant decrease at 2 weeks post-intervention in symptoms of anxiety (P &lt; .001) and depression (P = .042) and hopelessness (P = .017) and a significant improvement in mental well-being (P = .037) and parent-child relationships (P = .003) for the PC-SMILE group, and the enhancement in parent-child relationships sustained at the 3-months follow-up (P = .004). Moderation analysis showed that participants with higher baseline depression and anxiety levels and girls exhibited greater improvements in depression and anxiety symptoms. </sec> <sec> <title>CONCLUSIONS</title> The PC-SMILE intervention showed preliminary evidence of effectiveness in reducing adolescent anxiety and depression and improving parent-child relationships. Our findings revealed the potential benefits of brief online interventions for adolescents and parents, which may be scalable, destigmatized, and cost-effective alternatives to school-based programs. Future studies should focus on using mixed methods to evaluate outcome, and improve and amplify the effects of single-session interventions for adolescents. </sec> <sec> <title>CLINICALTRIAL</title> ClinicalTrials.gov NCT05493865 </sec> <sec> <title>INTERNATIONAL REGISTERED REPORT</title> RR2-10.2196/63220 </sec>