How is insomnia affecting your life?
The Insomnia Severity Index (ISI) was created by Charles Morin and validated by Bastien, Vallières and Morin (2001). It's the most widely used scale in clinical research and practice for quantifying how severe a sleep problem is and how it impacts daily functioning.
It evaluates three dimensions: difficulty initiating and maintaining sleep, satisfaction with current sleep, and impact on daytime functioning. It covers the past two weeks.
Key limitation: the ISI doesn't distinguish between primary insomnia and insomnia secondary to other conditions (depression, sleep apnea, chronic pain). A high score is a signal for evaluation, not a definitive diagnosis.
ISI — Insomnia Severity Index
Developed by Morin (1993) and validated by Bastien et al. (2001), the ISI is the standard scale for evaluating insomnia severity and its impact on daily functioning.
Validated by: Bastien, Vallières & Morin (2001); Morin (2011)
References
Frequently asked questions
Can the ISI diagnose insomnia?
No. The ISI is a screening tool. A diagnosis requires a full clinical evaluation ruling out medical causes and other sleep disorders.
What is CBT-I?
Cognitive Behavioral Therapy for Insomnia is the treatment with the strongest evidence for chronic insomnia, recommended as first-line before medication in European and American guidelines.
Are my answers stored?
No. All processing happens in your browser. We don't store any data.
How long do I need to have sleep problems for them to "count"?
The ISI assesses the past two weeks. For a clinical diagnosis, problems need to occur at least 3 nights/week for at least 3 months.