This study will compare the efficacy of an interactive Internet intervention for adult insomnia (Sleep Healthy Using the Internet; SHUTi) to that of a static educational website to improve sleep, mood related symptoms, perceived health status, and overall quality of life.

Insomnia is defined by complaints of poor sleep, as well as difficulties initiating and/or maintaining sleep more than 3 nights/week for more than 6 months. Insomnia may contribute to daytime fatigue, impaired performance, confused thinking and judgment, and difficulty with work and personal tasks. Cognitive behavioral therapy (CBT) has been found to have significant short- and long-term benefits for people with insomnia. Access to CBT for many people, however, is limited, due to the high cost of treatment and a limited number of trained professionals. Delivering CBT for insomnia via the Internet could help make it more widely available. This study will compare the effectiveness of an online CBT intervention in improving sleep, mood, and quality of life in people with insomnia to that of a static educational website.

Participants in this study will be randomly assigned to receive the online CBT intervention or the static patient education website. The intervention period will last for 9 weeks. During the intervention period, participants assigned to the patient education website will be given content addressing strategies for dealing with insomnia. Those assigned to use the Internet intervention will review interactive, tailored content specific to the user's difficulties. Participants will complete questionnaires and two weeks of daily sleep diaries about their symptoms at four time points - at the beginning of the study, immediately after completing the 9 week program, 6 months later, and 12 months later.

Inclusion Criteria:

• Age between 21 and 65 years old.
• Have sleep-onset insomnia and/or sleep maintenance insomnia (>30 minutes for at least 3 nights/week).
• Have insomnia symptoms lasting at least 6 months.
• Have an average total sleep time ≤ 6.5 hours.
• Sleep disturbances (or associated daytime fatigue) cause significant distress or impairment in social, occupational, or other areas of functioning.
• Have regular access to a computer and the Internet.
• Reside in the United States or are US Citizens living outside the United States

Exclusion Criteria:

• Pregnancy
• Report of a physical illness which is deemed active, unstable, degenerative, and/or progressive, such as congestive heart failure, dementia, or acute pain.
• Bipolar disorder as defined by a manic or hypomanic episode or treatment within the past 10 years.
• Severe depression.
• Endorse risk of suicide.
• Endorse alcohol or drug abuse within the past year.
• Presence of another untreated sleep disorder (e.g., sleep apnea, periodic leg movements).
• Have irregular sleep schedules, with usual bedtimes earlier than 8:00pm or later than 2:00am or arising times earlier than 4:00am or later than 10:00am.
• Current psychological treatment for insomnia.
• Initiating psychological treatment within past 3 months.
• Unstable medication regimen (change to schedule or dosage within past 3 months) for a medication regimen thought to impact sleep.