BACKGROUND: Adolescent depression is one of the largest health issues in the world and there is a pressing need for effective and accessible treatments.

OBJECTIVE: This trial examines whether affect-focused internet-based psychodynamic therapy (IPDT) with therapist support is more effective than an internet-based supportive control condition on reducing depression in adolescents.

METHODS: The trial included 76 adolescents (61/76, 80% female; mean age 16.6 years), self-referred via an open access website and fulfilling criteria for major depressive disorder. Adolescents were randomized to 8 weeks of IPDT (38/76, 50%) or supportive control (38/76, 50%). The primary outcome was self-reported depressive symptoms, measured with the Quick Inventory of Depressive Symptomatology for Adolescents (QIDS-A17-SR). Secondary outcomes were anxiety severity, emotion regulation, self-compassion, and an additional depression measure. Assessments were made at baseline, postassessment, and at 6 months follow-up, in addition to weekly assessments of the primary outcome measure as well as emotion regulation during treatment.

RESULTS: IPDT was significantly more effective than the control condition in reducing depression (d=0.82, P=.01), the result of which was corroborated by the second depression measure (d=0.80, P<.001). IPDT was also significantly more effective in reducing anxiety (d=0.78, P<.001) and increasing emotion regulation (d=0.97, P<.001) and self-compassion (d=0.65, P=.003). Significantly more patients in the IPDT group compared to the control group met criteria for response (56% vs 21%, respectively) and remission (35% vs 8%, respectively). Results on depression and anxiety symptoms were stable at 6 months follow-up. On average, participants completed 5.8 (SD 2.4) of the 8 modules.

CONCLUSIONS: IPDT may be an effective intervention to reduce adolescent depression. Further research is needed, including comparisons with other treatments.

TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number (ISRCTN) 16206254; http://www.isrctn.com/ISRCTN16206254.