A single‐session growth mindset intervention for adolescent anxiety and depression: 9‐month outcomes of a randomized trial

Background Single‐session interventions ( SSI s) show promise in the prevention and treatment of youth psychopathology, carrying potential to improve the scalability and accessibility of youth psychological services. However, existing SSI s have conferred greater benefits for youths with anxiety, compared to depression or comorbid problems, and their effects have generally waned over time – particularly for follow‐ups exceeding 3 months. Method To help address these discrepancies, we tested whether a novel SSI teaching growth mindset of personality (the belief that personality is malleable) could reduce depression and anxiety and strengthen perceived control in high‐risk adolescents ( N  = 96, ages 12–15). At baseline, youths were randomized to receive a 30‐min, computer‐guided growth mindset intervention or a supportive‐therapy control. Youths and parents reported youth anxiety and depressive symptoms, and youths reported their levels of perceived control, at baseline and across a 9‐month follow‐up period. Results Compared to the control program, the mindset intervention led to significantly greater improvements in parent‐reported youth depression (d  =   .60) and anxiety ( d  =   .28), youth‐reported youth depression ( d  =   .32), and youth‐reported perceived behavioral control ( d  =   .29) by 9‐month follow‐up. Intervention effects were nonsignificant for youth‐reported anxiety, although 9‐month effect sizes reached the small‐to‐medium range ( d  =   .33). Intervention group youths also experienced more rapid improvements in parent‐reported depression, youth‐reported depression, and perceived behavioral control across the follow‐up period, compared to control group youths. Conclusions Findings suggest a promising, scalable SSI for reducing internalizing distress in high‐risk adolescents. Clinical Trial Registration Number: NCT 03132298.