The object of this study is to determine whether feedback added to a self-help protocol for
insomnia enhances the treatment effect. In this study all participants receive an online
self-help cognitive behavioral therapy (CBT) intervention consisting of information
(psycho-education) about sleep and cognitive-behavioural exercises. Adult persons with
insomnia will be invited via a popular scientific website to fill out online questionnaires.
Half of the participants will received by e-mail from a therapist, the other half of the
participants will do the intervention without feedback. Participants will be measured 4, 16,
and 40 weeks after intervention with the same questionnaires.