The Insomnia Severity Index (ISU) is based on elements of insomnia used in the DSM-IV.
Patient selection: insomnia
Parameters:
(1) difficulty (delay) with sleep onset
(2) difficulty with sleep maintenance
(3) problem with early awakening
(4) satisfaction with sleep pattern
(5) interference with daily functioning caused by sleep problems
(6) noticeability of sleep problem to others
(7) distress cause by the sleep problem
|
Responses to Items 1 to 3
|
Points
|
|
none
|
0
|
|
mild
|
1
|
|
moderate
|
2
|
|
severe
|
3
|
|
very severe (extreme)
|
4
|
|
Response for Item 4
|
Points
|
|
very satisfied
|
0
|
|
satisfied
|
1
|
|
neutral
|
2
|
|
dissatisfied
|
3
|
|
very dissatisfied
|
4
|
|
Responses for Items 5 to 7
|
Points
|
|
not at all
|
0
|
|
a little
|
1
|
|
somewhat
|
2
|
|
much
|
3
|
|
very much
|
4
|
total ISI =
= SUM(points for all 7 parameters)
Interpretation:
• minimum score: 0
• maximum score: 28
• The higher the score the more severe the insomnia.
• Morin et al found a score >= 10 indicative of insomnia in a community sample, with a decrease of more than 8 points evidence of moderate improvement after an intervention.
• Savard et al used an ISI >= 8 as indicative insomnia in a cohort of cancer patients.
