The intervention group receives the login data for the online program directly following the baseline assessment. The program consists of 9 modules with many interactional exercises. Themes that are addressed in the online-program are for example self-esteem, coping with relapse, establishing a structure for daily life and attention and breathing exercises as well as depression-specific topics such as negative thoughts management and arranging and maintaining social contacts. In addition, participants were able to participate in exchange with peers via an internal closed forum.

The participants of the wait-list control condition do not receive any new intervention during the intervention period of 9 weeks, but may continue any treatment that has already been started before, including medication. Participants in the wait-list control condition receive full access to the program after completion of the post-assessment.

The intervention group receives the login data for the online program directly following the baseline assessment. The program consists of 9 modules with many interactional exercises. Themes that are addressed in the online-program are for example self-esteem, coping with relapse, establishing a structure for daily life and attention and breathing exercises as well as depression-specific topics such as negative thoughts management and arranging and maintaining social contacts. In addition, participants were able to talk about personal experiences and difficulties concerning the program on a weekly basis with a therapeutic guide on the phone.

The program consists of 9 modules with many interactional exercises. Themes that are addressed in the online-program are for example self-esteem, coping with relapse, establishing a structure for daily life and attention and breathing exercises as well as depression-specific topics such as negative thoughts management and arranging and maintaining social contacts. In addition, participants were able to talk about personal experiences with a therapeutic guide.

The PHQ-9 (Kroenke et al. 2001) is made up of 9 items which could be self-rated on a 4-point Likert scale ranging from 0 (not at all) to 3 (nearly every day). Major depression and other depression diagnoses according to DSM-IV can be determined according to the overall score. Sum scores of 0-4 indicate none or minimal depressive symptoms, 5-9 mild depressive symptoms, 10-14 moderate depressive symptoms, and 15-27 severe depressive symptoms. Its internal consistency ranges from 0.86-0.89 (Smarr and Keefer 2011).

The BDI-II (Beck et al., 1996) is a 21-item self-report inventory measuring the severity of depression in adolescents and adults. Each item is rated on a four-point Likert scale ranging from 0 (symptom not present) to 3 (symptom very intense). The BDI assesses psychological and physical symptoms over the last two weeks in order to quantify levels of depression. An overall score of 0-13 indicates minimal depression, a score of 14-19 indicates mild depression, a score of 20-28 moderate depression and total scores of 29-63 suggest severe depression. The internal consistency of the BDI-II ranges from 0.79-0.90 (Smarr and Keefer 2011).

The WHOQOL-BREF is a shorter version of the World Health Organization Quality of Life-100 (The WHOQOL Group 1998). It is composed of 26 self-report items measuring domains such as physical health, psychological health, social relationships and environment with the aim of measuring changes in quality of life over the course of treatment. Four different types of 5-point Likert scales are applied, asking "how much", "how complete", "how often", "how good" or "how satisfied" the person felt concerning the past two weeks. The WHOQOL-BREF has an internal consistency of .70 (Skevington, Lotfy, & O'Connell, 2004).