Insomnia Severity Index (ISI) Assessment

Introduction:

Insomnia Severity Index (ISI) is a widely used seven-item questionnaire developed to quantify perceived difficulty initiating or maintaining sleep and the related daytime burden. It converts subjective ratings into a single numerical score, enabling clinicians and individuals to track symptom change across time and compare severity levels against validated thresholds.

This interactive page lets you complete the index on any modern device. You select one of five severity options—None through Very Severe—for each statement, and the tool instantly sums your choices, classifies the total into one of four evidence-based bands, and visualises the result with a simple gauge to clarify where you land on the 0–28 spectrum.

Use it to monitor progress during sleep-hygiene experiments, share consistent snapshots with a therapist, or screen the likely impact of disruptive schedules before travel. Because the outcome depends on self-report and cannot capture medical comorbidities, treat the score as guidance only, not diagnosis; results do not constitute a clinical diagnosis.

Technical Details:

Insomnia Severity Index transforms ordinal self-ratings into a quantitative indicator of insomnia impact. Each question targets a dimension—sleep onset, maintenance, early awakening, satisfaction, day-time impairment, external noticeability, and distress. Summing the seven 0–4 responses yields a 0–28 composite approximating both nocturnal difficulty and functional consequences. Clinically, the measure tracks intervention response and flags when professional evaluation is advisable. It has demonstrated strong internal consistency and correlates well with polysomnography-derived markers across diverse populations.

• Difficulty falling asleep – perceived trouble initiating sleep.
• Difficulty staying asleep – frequency of night awakenings.
• Waking too early – undesired early final awakening.
• Sleep satisfaction – subjective contentment with pattern.
• Day-time impact – interference with daily activities.
• Noticeability – how obvious the problem is to others.
• Worry or distress – concern caused by the sleep issue.

• Assumes honest self-report without recall bias.
• Captures past two weeks only; longer trajectories need repeated use.
• Ignores medical factors such as sleep-apnoea surprise.
• Validated mainly in adults; paediatric norms differ.

• Leaving items blank produces an indeterminate score.
• Answering all zeros collapses gauge to baseline.
• Extreme life events may inflate ratings independently of insomnia.
• Shift-workers may misinterpret “night-time” framing.

Primary validation: Bastien et al., Sleep Medicine (2001); comparative studies in oncology cohorts and older adults corroborate factor structure and sensitivity to change.

All calculations occur locally; no personal data leaves your browser, aligning with GDPR principles of data minimisation.

Step-by-Step Guide:

Follow these actions to obtain an accurate score.

1. Click Start Assessment.
2. Select one response for each of the seven statements.
3. Review progress in the side list; unanswered items show no tick.
4. When complete, read the gauge, band label, and personalised guidance.

FAQ:

Glossary:

Insomnia

Persistent difficulty with sleep initiation, duration or quality.

Sleep Onset Latency

Time taken to transition from wakefulness to sleep.

Day-time Impairment

Functional limitation experienced while awake.

Severity Band

Descriptive category linked to a score range.

Polysomnography

Comprehensive overnight sleep study measuring physiological signals.