Impact of the best possible self intervention on affective well-being in early adolescence: A randomized controlled online trial

The Best Possible Self intervention (BPS) has demonstrated efficacy in promoting well-being in various populations, yet its impact in adolescence is under-researched. Our study investigated the feasibility and efficacy of the BPS in early adolescence (11-15 years) to promote positive affect and reduce negative affect. We conducted a randomized controlled online trial (<i>N</i> = 200, <i>M</i> _<i>age</i> = 14.01 years, <i>SD</i> = 1.19, 78.5 % female). Participants were assigned to the BPS group (<i>n</i> = 59), a writing control group (<i>n</i> = 68), or a non-writing control group (<i>n</i> = 73). Affect (PANAS-C-SF) was measured immediately before and after the intervention. The BPS demonstrated feasibility in our sample and significantly increased positive affect post-intervention compared to both control groups, suggesting a mood-boosting effect. The BPS did not significantly reduce negative affect post-intervention relative to the control groups. Our findings provide initial evidence that the BPS is a feasible and effective intervention for enhancing positive affect in early adolescence. Future research should explore its long-term effects, repeated administration, and potential for implementation in group settings to maximize its impact.