Insomnia Severity Index (ISI)
Standardized self-report measure of insomnia severity over the past 2 weeks
The Insomnia Severity Index (ISI), developed by Bastien, Vallières & Morin (2001), is a widely used 7-item self-report questionnaire assessing the severity of sleep onset, maintenance, and early morning awakening problems, as well as satisfaction with current sleep, interference with daily functioning, noticeability of impairment, and level of distress. Total score 0-28. Cutoffs: 0-7 no insomnia, 8-14 mild/moderate, 15-21 moderate, 22-28 severe. Takes about 3-5 minutes.
What Is the Insomnia Severity Index (ISI)?
The Insomnia Severity Index (ISI), developed by Bastien, Vallières & Morin (2001), is a brief self-report instrument measuring a patient's perception of insomnia severity. It is one of the most widely used insomnia assessment tools in both clinical and research settings.
Scale Structure
The ISI contains 7 items covering the core dimensions of insomnia:
- Sleep difficulty severity (Q1-Q3): difficulty falling asleep, staying asleep, early morning awakening
- Sleep satisfaction (Q4): subjective satisfaction with current sleep pattern
- Daytime functioning impact (Q5): interference with daily functioning
- Noticeability (Q6): how noticeable the impairment is to others
- Distress (Q7): level of worry/distress about the sleep problem
Scoring
Each item rated 0-4, total score 0-28. Higher scores indicate more severe insomnia.
Clinical Cutoffs
- 0-7: No clinically significant insomnia
- 8-14: Mild to moderate insomnia symptoms
- 15-21: Moderate insomnia (warrants evaluation and treatment)
- 22-28: Severe insomnia (immediate professional help recommended)
Psychometric Properties
The ISI has strong psychometric properties (Bastien et al., 2001):
- Internal consistency: α = 0.90-0.91
- Test-retest reliability: r = 0.83
- Good convergent validity with sleep diary measures
- Good sensitivity and specificity at various cutoffs
Reference
Bastien, C. H., Vallières, A., & Morin, C. M. (2001). Validation of the Insomnia Severity Index as an outcome measure for insomnia research. *Sleep Medicine*, 2(4), 297-307.
Morin, C. M. (1993). *Insomnia: Psychological Assessment and Management*. New York: Guilford Press.
Scoring Guide
Sum all 7 items (each rated 0-4) for a total score of 0-28. 0-7 = no clinically significant insomnia; 8-14 = mild/moderate insomnia symptoms; 15-21 = moderate insomnia; 22-28 = severe insomnia. Note: Q4 (satisfaction) is reverse-keyed in concept but scored consistently (0=very satisfied, 4=very dissatisfied) and summed directly.
Result Interpretation
After completing the 7 questions, you'll receive an immediate, detailed report with:
- Your score — calculated automatically based on your responses
- Score interpretation — what your score means in practical terms
- Context — how your results compare to general population norms where available
All results are displayed instantly on screen. No account, email, or login required.