The Swiss company mementor has recently developed an interactive self-help intervention for the treatment of insomnia entitled mementor somnium. This programme is based on the guidelines for cognitive-behavioural therapy. mementor somnium consists of 6 online sessions. An animated personal sleep coach provides relevant audio-information and asks questions to which the patient is invited to respond. The components of the programme flexibly adapt to the patient's responses. Aside from psycho-education, exercises and an instruction for sleep restriction, mementor somnium includes a cognitive restructuring intervention in terms of a Socratic dialogue. This Socratic dialogue, implemented by the animated sleep coach, is based on a complex algorithm in the shape of an decision tree. University of Zurich's Department of Psychology in Switzerland will test the effectiveness of mementor somnium in a randomised controlled trial with three assessment times (pre, 6-weeks post and 3-months follow-up). Patients suffering from insomnia will be allocated randomly to either the active intervention group or the waitlist control group. Participants will have access to the programme mementor somnium for six weeks. Primary outcome measure is the Insomnia Severity Index, secondary outcome measures are Beck Depressions-Inventory revised (BDI-II), Brief Symptom Inventory 18, and the SF-12 Health Survey. Additionally, sleep diary data will be collected.

Inclusion Criteria:

• Insomnia Disorder (DSM-5)
• German language comprehension
• Internet-access

Exclusion Criteria:

• Other sleep disorder
• Suicidality
• Current psychotherapy
• Drug abuse or recent change in medication