The study will test an internet-based treatment for insomnia.

This study will develop and evaluate the feasibility of a cost-effective, more accessible alternative treatment approach for insomnia. Traditional CBT, including the behavioral, cognitive, and educational aspects, will be operationalized and transformed for an Internet intervention system, so individuals can access a personalized treatment any time, at their own convenience. Phase 1 of this study will involve developing the web program. The investigators research team and collaborators has extensive experience developing such web interventions, as well as considerable experience with insomnia. Phase 2 will be a large randomized controlled trial testing the Internet intervention compared to passive patient education/sleep hygiene. Two hundred individuals with insomnia will be assessed pre and post the six week treatment program. It is hypothesized that the Internet intervention will promote improvements in sleep, mood, and cognitive functioning. If successful, the current project may result in improved implementation of a low-threshold treatment for a common disorder with devastating impact on both individual and socioeconomic outcomes

Inclusion Criteria:

1. age 18 years or older
2. fulfillment of the DMS-IV criteria for insomnia
3. duration of at least 3 months
4. complaints of impaired daytime functioning

Exclusion Criteria:

1. presence of a major depressive disorder or other severe mental disorder as identified by in the telephone interview
2. working night shifts and unable to discontinue this work pattern
3. having a serious somatic condition preventing further participation.