In this study, people who suffer from adjustment problems after having experienced an accident will be randomized to one of two study groups. The first group receives access to the internet-based self-help intervention immediately. The second group is a waiting control group that receives access to the program 12 weeks later. In both conditions additional care or treatment is allowed. The aim of the study is to investigate the efficacy and cost-effectiveness of an internet-based self-help intervention for people with adjustment problems after an accident compared to a waiting list. There are 6 assessments, which all take place online: baseline, two between-measurements (after 4 and 8 weeks), post assessment (after 12 weeks) and two follow-up assessments (after 3 and 6 months). All participants from both groups are asked to fill out all assessments.

Inclusion Criteria: All participants must...

• be at least 18 years old
• give a declaration of consent to participate in the study
• have access to the Internet
• understand and master the German language to the degree that they understand the contents and instructions of the study
• exceed the cut-off value for at least a mild psychological burden on the depression-anxiety stress scale (DASS- 21)
• be able to specify an emergency address in the event of an acute crisis
• have experienced and can specify an accident during a period of two weeks to two years prior to participation in the current study that lead to the conditions described above.

Exclusion Criteria: Excluded are persons who...

• show severe depressive symptoms (Beck depression inventory [BDI-II] > 29)
• show suicidal tendencies (BDI-II Suicide item > 1)
• have a known diagnosis of psychotic or bipolar disorder.