Two Year Outcomes of a Randomized Control Trial of an Internet-Base Adolescent Depression Prevention Intervention in Primary Care

Introduction: Depression is a leading cause of illness and disability in adolescents worldwide, and scalable interventions with long term follow-up in primary care settings remain limited. Competent Adulthood Transition with Cognitive Behavioral Humanistic and Interpersonal Psychotherapy (CATCH-IT) is an internet-based teen depression prevention intervention that has been found to reduce the risk of developing a depressive episode among symptomatic teens in primary care. We explore the long-term effects of CATCH-IT compared to a general health education (HE) program in a multicenter randomized controlled trial with 24 month follow-up.

Methods: We screened 8499 teens (ages 13-18) from 2012 to 2016. We randomized 369 eligible teens (Mean [SD] age=15.4 [1.5]) with sub-syndromal and/or history of depression with a prior DSR≥3 (62%) and DSR≥4 (40%). The cohort self-identified as moderately depressed (Mean [SD] CES-D₁₀=9.4 [4.6]) and functionally impaired (Mean [SD] GAS=78.1 [9.4]) with moderate anxiety (Mean [SD] SCARED=25.3 [12.3]). Participants were assessed at 2, 6, 12, 18, and 24 months.

Results: In intention-to-treat (ITT) analyses, there was not a statistically significant effect for CATCH-IT at 24 months (adjusted HR=0.86, 95% CI, 0.51, 1.47, p=0.59). Per protocol 2 (2 modules completed) analysis favored CATCH-IT over HE at 6 months (unadjusted HR=0.41; 95% CI, 0.17, 0.99, p=0.047), but results attenuated at 12 months (HR=0.65, 95% CI, 0.34, 1.21, p-value=0.17) and similarly at 24 months (HR=0.71, 95% CI, 0.41, 1.23, p=0.22). At 6 months, adolescents with higher baseline CES-D₁₀ scores showed a stronger effect of CATCH-IT on time to event, but this effect was not seen at 24 months. Demographics, vulnerability factors, adverse life events, motivation, and parent/child comorbid psychopathology did not moderate outcome. The overall annual incidence of major depressive episodes remained low in both arms, 5.4% in HE and 4.6% in CATCH-IT. Relative to baseline, at 24 months adolescents in the CATCH-IT group reported fewer symptoms of depression (adjusted mean change=-1.6, p=.006) and anxiety (-3.2, p=.03), while symptom reductions were only marginally significant for adolescents in the HE group (-0.9, p=.07 for depression; -2.5, p=.08 for anxiety). Across groups, GAS scores improved over time (9.7, 9.6; p<.001).

Discussion: The incidence of depressive episodes was lower than expected for a high risk sample in CATCH-IT and HE, suggesting protective elements common to both interventions. These findings suggest several benefits to investing in internet based tele-health systems for at-risk adolescents. This is the first long-term, population-based trial of a scalable intervention to prevent teen depression in the primary care setting.