ISI: Insomnia Severity Index
The ISI (Insomnia Severity Index) is a 7-item self-report questionnaire that measures the perceived severity of insomnia symptoms over the past two weeks. Total scores range from 0 to 28 across four severity bands, and it is a primary outcome measure in CBT-I trials.
ISI Score Calculator
Enter each of the 7 items (0–4) to total them and see the band. Items are numbered, not reproduced — enter them from the form in front of you. Scoring aid only; it does not diagnose.
Score in the range associated with no clinically significant insomnia in validation samples.
0 of 7 items entered — 7 still blank. The total can only rise, so treat the band above as provisional.
Each item scores 0–4. Items are numbered, not reproduced — enter them from the form in front of you. Response anchors differ by item on this scale, so use the wording printed on the form.
For reference only — not an assessment, diagnosis, or medical advice. This page provides scoring reference material; interpretation and clinical decisions rest with a qualified clinician.
ISI Score Interpreter
Score indicates clinical insomnia of moderate severity; further assessment and treatment planning are recommended.
7 items, each rated 0–4; total score 0–28. Higher scores indicate greater insomnia severity.
| Total score | Interpretation |
|---|---|
| 22+ | Severe clinical insomniaScore indicates severe insomnia warranting prompt clinical evaluation and evidence-based treatment such as CBT-I. |
| 15–21 | Moderate clinical insomniaScore indicates clinical insomnia of moderate severity; further assessment and treatment planning are recommended. |
| 8–14 | Subthreshold insomniaScore suggests subthreshold insomnia; symptoms may warrant monitoring and preventive intervention. |
| 0–7 | No clinically significant insomniaScore in the range associated with no clinically significant insomnia in validation samples. |
Bastien et al. (2001); Morin et al. (2011). Severity bands per published validation studies. Educational reference only — not a diagnostic tool.
For reference only — not an assessment, diagnosis, or medical advice. This page provides scoring reference material; interpretation and clinical decisions rest with a qualified clinician.
HiBoop does not offer the ISI; this page is reference material. For sleep, HiBoop offers the PROMIS-based DSM-5 sleep disturbance measure to clinics that hold its licence, alongside the PHQ-9 and GAD-7, scored on submission and tracked over time.
What the ISI measures
The ISI (Insomnia Severity Index) is a validated 7-item self-report questionnaire for assessing the severity of insomnia symptoms. Developed by Morin (1993) and psychometrically validated by Bastien, Vallières and Morin (2001), it covers sleep-onset difficulty, sleep-maintenance difficulty, early morning awakenings, sleep dissatisfaction, functional impairment, noticeability to others, and distress about sleep.
The Insomnia Severity Index is one of the most widely used brief self-report measures for evaluating insomnia severity in both clinical practice and research. It assesses the current severity of insomnia symptoms over the past two weeks across seven dimensions, producing a total score that maps to four clinical severity bands. The ISI is widely used as an outcome measure in CBT-I trials and routine insomnia screening. For related tools, see our assessment library and measurement-based care resources.
How to administer the ISI
The ISI is completed by the patient and typically takes 5 minutes or less.
Instructions: Rate each of the following over the past 2 weeks.
All items use a 0–4 scale where 0 = None / Not at all and 4 = Very Severe / Very Much.
Severity of insomnia problems
How severe have your insomnia symptoms been in the past 2 weeks?
Sleep satisfaction
How satisfied / dissatisfied are you with your current sleep pattern?
Daily functioning
To what extent do you consider your sleep problem to interfere with your daily functioning (e.g., daytime fatigue, concentration, work performance, mood)?
Impact on quality of life
How noticeable to others do you think your sleeping problem is in terms of impairing the quality of your life?
Worry / distress
How worried / distressed are you about your current sleep problem?
ISI scoring and interpretation
Each item is rated on a 0–4 Likert scale and all items are summed; total scores range from 0 to 28. No items are reverse-scored. The ISI classifies insomnia into four categories: 0–7 (no clinically significant insomnia), 8–14 (subthreshold insomnia), 15–21 (clinical insomnia, moderate severity), and 22–28 (clinical insomnia, severe).
ISI item structure
Rates difficulty falling asleep, staying asleep, and waking too early (0=None to 4=Very Severe each)
Rates satisfaction with current sleep pattern (0=Very Satisfied to 4=Very Dissatisfied)
Rates extent that sleep problem interferes with daily functioning (0=Not at all to 4=Very Much)
How noticeable is the sleep problem to others in terms of quality of life impairment
Degree of worry or distress about the sleep problem (0=Not at all to 4=Very Much)
Documenting ISI results
ISI total score and severity band belong in the Objective section of your clinical note. See our SOAP notes guide for templates and documentation examples.
Psychometric properties
- Internal consistency: Cronbach's alpha of 0.90 and 0.91 in community and clinical samples (Morin et al., 2011) and 0.92 in primary care (Gagnon et al., 2013).
- Case detection: a cutoff of 10 was optimal for detecting insomnia in a community sample (86.1% sensitivity, 87.7% specificity; Morin et al., 2011). In primary care, a cutoff of 14 was optimal (82.4% sensitivity, 82.1% specificity; AUC 0.87; Gagnon et al., 2013).
- Treatment response: in a clinical sample, a change of -8.4 points was associated with moderate improvement rated by an independent assessor (Morin et al., 2011).
- Informant convergence: scores from the patient version converge closely with clinician and significant-other versions (Bastien et al., 2001).
- Widely used as a primary outcome measure in CBT-I randomized controlled trials (Edinger et al., Morin et al.).
- Validated in primary insomnia, cancer, chronic pain, depression, PTSD, and general community samples; translated into 40+ languages.
Limitations
- Screening, not diagnosis. A high ISI score warrants clinical evaluation; it does not constitute a diagnosis. Diagnosis requires a clinical interview that considers duration, frequency, daytime impairment, and exclusion of other causes.
- Perceived severity. The ISI captures the patient's perception of sleep difficulty, not objective sleep measured by diaries or polysomnography.
- Cutoffs vary by setting. The optimal case-detection cutoff differed between community (10) and primary care (14) samples.
Insomnia and comorbid mental health conditions
Insomnia is highly comorbid with depression, anxiety, and PTSD. In major depressive disorder, insomnia occurs in 60–80% of patients; in PTSD, sleep disturbance is a diagnostic criterion. CBT-I is effective even when insomnia is comorbid with these conditions.
When administering the ISI alongside mood or anxiety measures, document whether sleep difficulties are primary or secondary to determine treatment sequencing.
Original development: Morin, C. M. (1993). Insomnia: Psychological assessment and management. Guilford Press.
Copyright: The ISI is copyrighted by Prof. Charles M. Morin and distributed by Mapi Research Trust (ePROVIDE); licensing terms apply and vary by user type (academic, clinical, or commercial). Cite Morin et al. (2011) when using it in research.
HiBoop does not offer this scale. This page is reference material.This library is an academic and clinical reference. A scale described here is not necessarily offered in HiBoop; each page says whether it is.
Bill this assessment
In the US, the ISI: Insomnia Severity Index is usually billed under these CPT codes. Payer rules vary.
Measurement-based care in practice
For clinicians
HiBoop does not offer this scale. For the scales it does offer, responses are scored on submission and tracked over time, and HiBoop automates delivery across your patient panel.
For individuals
This page is a clinical reference, not a diagnostic tool. If you have concerns about your own symptoms, bring this information to a qualified mental health professional.
Frequently Asked Questions
How is the ISI scored?
The ISI contains 7 items, each rated on a 0–4 Likert scale. All item scores are summed to produce a total between 0 and 28. No items are reverse-scored.
What do ISI score ranges mean?
Scores of 0–7 indicate no clinically significant insomnia, 8–14 subthreshold insomnia, 15–21 moderate clinical insomnia, and 22–28 severe clinical insomnia. These bands were established in validation studies by Bastien et al. (2001) and Morin et al. (2011).
References
- 1.Morin CM, Belleville G, Bélanger L, Ivers H. The Insomnia Severity Index: psychometric indicators to detect insomnia cases and evaluate treatment response. Sleep. 2011;34(5):601-608.View source
- 2.Bastien CH, Vallières A, Morin CM. Validation of the Insomnia Severity Index as an outcome measure for insomnia research. Sleep Med. 2001;2(4):297-307.View source
- 3.Gagnon C, Bélanger L, Ivers H, Morin CM. Validation of the Insomnia Severity Index in primary care. J Am Board Fam Med. 2013;26(6):701-10.View source
Last reviewed: Jun 3, 2026
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