Is internet-delivered therapy more effective than internet-delivered brief support in reducing depressive symptoms in adolescents?

INTERVENTION: Directly after inclusion, participants will be randomized to one of two arms with 1:1 ratio: intervention or control condition. An independent researcher, not involved in the study, will conduct the randomisation procedure by means of a computerised random number service. Intervention: Internet‐delivered psychodynamic treatment (I‐PDT) that consists of 8 therapist‐supported self‐help modules delivered over 8 weeks in a secure online platform. Modules consist of texts followed by assignments which they send to their therapist and receive feedback within a few days, complemented with 30 minutes chat support weekly. The aim of I‐PDT is to decrease emotional avoidance and increase awareness and experience of emotions. Participants are encouraged to gradually approach previously warded off feelings. They will also be taught how to link their emotions to their symptoms. Another treatment goal is to acquire a greater capacity for anxiety regulation. Treatment duration is 8 weeks and measurements are made prior to treatment, weekly during treatment, and at termination. Control condition: Brief supportive contact over internet over 8 weeks, with monitoring of symptoms and well‐being as well as exchange of short messages between participant and therapist. Duration is 8 weeks and measurements are made prior to the supportive contact, weekly during the supportive contact, and at termination. After 10 weeks, participants in the control condition will be offered the I‐PDT‐program with email‐support. New measurements will be made weekly during the treatment and at termination. CONDITION: Mild to moderate depression in adolescents ; Mental and Behavioural Disorders PRIMARY OUTCOME: ; 1. Depressive symptoms will be measured using the Quick Inventory of Depressive Symptomatology in Adolescents (Bernstein et al., 2010) via internet delivered self‐rating forms pre‐treatment, weekly during treatment and post‐treatment.; 1.1. In order to fully explore trajectories of change and possible moderating and mediating factors over time, a parallel process latent growth curve strategy will be employed.; 2. Differences in efficacy between conditions will be investigated by modelling interaction effects of group and time.; SECONDARY OUTCOME: ; 1. Anxiety symptoms will be measured weekly using the Generalised Anxiety Disorder 7‐ item scale (GAD‐7; Kroenke et al., 2010).; 2. The severity of depression symptoms will be measured pre‐ and post‐treatment using the Montgomery Ã…sberg Depression Rating Scale (Svanborg & Ã…sberg, 1994).; INCLUSION CRITERIA: 1. Adolescents 15‐18 years of age 2. Suffering from mild to moderate symptoms of depression according to a diagnostic interview (MINI 7.0). 3. Have access to a computer/smartphone/tablet with internet connection 4. Able to read, write and speak Swedish without the aid of an interpreter.