Insomnia Severity Index

What it measures

A brief measure of perceived insomnia severity, including difficulty falling asleep, staying asleep, early morning awakening, satisfaction with sleep, interference with daily functioning, noticeability of impairment, and distress. Widely used as an outcome measure in CBT-I trials.

Response format

Likert (0–4 per item); total 0–28

Representative items

• Difficulty falling asleep (0=none to 4=very severe)
• Difficulty staying asleep (0=none to 4=very severe)
• Problems waking up too early (0=none to 4=very severe)
• How satisfied/dissatisfied are you with your current sleep pattern? (0=very satisfied to 4=very dissatisfied)
• How noticeable to others do you think your sleep problem is?

Usage notes & scoring

Score ranges: 0–7 no clinically significant insomnia, 8–14 subthreshold, 15–21 moderate clinical insomnia, 22–28 severe. Freely available. Primary outcome in most CBT for Insomnia (CBT-I) trials. Validated in numerous languages.

Recommended companion scales

Citation

Morin, C.M. (1993). Insomnia: Psychological assessment and management. Guilford Press.

Keywords