Insomnia Severity Index score: ranges and next steps

An Insomnia Severity Index (ISI) score runs from 0 to 28 and shows how much trouble you’ve had with sleep over the last two weeks, and how much it’s bothering you. The ranges are 0 to 7 (few sleep problems), 8 to 14 (some sleep trouble), 15 to 21 (sleep is a struggle) and 22 to 28 (sleep is very hard). From 15 up, sleep trouble is affecting you enough that talking to a doctor is a good next step. The score is a measure of how you’re sleeping, not a diagnosis of insomnia.

What is the Insomnia Severity Index?

The Insomnia Severity Index is a seven-question check of how much trouble you’re having with sleep. It was developed by Canadian psychologist Charles Morin, first described in his 1993 book on the assessment and treatment of insomnia, and tested as a measure of treatment progress by Bastien, Vallières and Morin in a 2001 paper in Sleep Medicine. Sleep clinics and researchers around the world use it, both to see how severe sleep trouble is and to track whether treatment is helping.

It looks at the last two weeks, so it’s a snapshot of how you’re sleeping now rather than over months. That makes it a good fit for anyone who lies awake, wakes in the night or wakes too early, and wants to know whether it’s “bad enough” to mention to someone.

The insomnia check on Sprout uses the Insomnia Severity Index and takes about two minutes. Taking the test is free; results need Sprout Plus (7 days free).

What does the ISI ask, and how are the answers scored?

Three questions ask about your nights and four ask about how sleep is affecting you. Each answer scores from 0 to 4, and the seven are added together for a total from 0 to 28.

1. How much trouble have you had falling asleep?
2. How much trouble have you had staying asleep?
3. How much trouble have you had with waking up too early?
4. How satisfied are you with your sleep right now?
5. How much do you think other people notice that sleep problems are affecting your life?
6. How worried or distressed are you about your sleep right now?
7. How much are sleep problems getting in the way of your days, like your energy, mood, work, focus or memory?

On Sprout, the first three questions are answered from None (0) through A little, Some and A lot to Very much (4). The satisfaction question runs from Very satisfied (0) to Very dissatisfied (4), and the last three from Not at all (0) to Very much (4). There’s no weighting: the total is just the seven numbers added up.

Only three of the seven questions are about the nights themselves. The other four are about satisfaction, worry and daytime effects. Insomnia isn’t defined by hours alone. Someone who sleeps six hours and feels fine has a different problem, or no problem, compared with someone who sleeps six hours and dreads every bedtime.

What do the ISI score ranges mean?

Your total falls into one of four ranges. Sprout gives them plain names; the scale’s scoring guidelines, from Morin’s work, use clinical ones.

0 to 7: few sleep problems

Sleep hasn’t been causing you much trouble. You may have the odd restless night, like everyone does, but it doesn’t seem to be getting in the way of your days. It can help to notice what’s working, such as a regular bedtime or a wind-down routine, so you can come back to it if sleep gets harder.

8 to 14: some sleep trouble

You’ve had some trouble with sleep, on the milder side. Maybe it takes a while to drop off, you wake in the night, or you wake earlier than you’d like, and it’s starting to bother you a little. This is very common, especially during stressful or busy times. Steady wake-up times, less screen time before bed and some daylight in the morning can all help. Checking in again in a couple of weeks shows whether things are settling.

15 to 21: sleep is a struggle

Sleep seems to have been a real struggle, and it’s probably affecting how you feel and cope during the day. Poor sleep can wear down mood, energy and concentration. You don’t have to just put up with it: there are well-proven approaches that help many people sleep better, and a doctor can talk you through them.

22 to 28: sleep is very hard

Sleep seems to have been very difficult, and it’s likely taking a big toll on your days. That can be exhausting and worrying, and it makes sense if everything feels harder right now. Long-lasting sleep problems are common and treatable, and getting support is a good step. Take extra care with driving or other risky tasks when you’re very tired.

What does an ISI score of 15 mean?

A score of 15 puts you at the start of the sleep is a struggle range, which the scale’s guidelines call moderate clinical insomnia. It means sleep trouble has been frequent enough, and has bothered you enough, over the last two weeks that it’s worth taking to a doctor rather than waiting.

It doesn’t mean you’ve been diagnosed with insomnia. A diagnosis also looks at how long it has gone on and what else might explain it. In the DSM-5, the manual many clinicians use, insomnia disorder means trouble sleeping on at least three nights a week for at least three months, despite having enough chance to sleep, and with real effects on your days. The ISI covers two weeks, so a doctor will ask how long this has been happening.

Scores just under the line count too. Someone at 13 who is struggling at work deserves help as much as someone at 16. Morin and colleagues found in a 2011 study in the journal Sleep that, in the general community rather than in sleep clinics, a lower cut-off of 10 was better at picking out people with insomnia. So if you’re in the 10 to 14 part of the some sleep trouble range and it has been going on for a while, it’s still worth mentioning.

Can the ISI tell you if you have insomnia?

No. It shows how much trouble you’ve had with sleep recently and how much it bothers you, but only a doctor or sleep specialist can assess a sleep disorder. A questionnaire can’t take your history or look for the things that sometimes sit behind poor sleep.

Some of the things a doctor will want to know about:

• How long it’s been going on. A few bad weeks after a stressful event is different from a pattern lasting months.
• What happens during sleep. Loud snoring, gasping or pauses in breathing, often noticed by a partner, point to a different kind of sleep problem.
• Your health and medicines. Pain, needing the toilet at night, hot flushes, some medicines and caffeine or alcohol can all disturb sleep.
• Mood and worry. Poor sleep and low mood or anxiety often travel together, and each can make the other worse.
• Your daytime sleepiness. People with insomnia often feel tired but can’t nap. Struggling to stay awake during the day is a different signal, and the ESS score ranges describe it.

Why can your ISI score be high when you sleep more than you think?

Because the ISI measures how much sleep is troubling you, not just how much you sleep. Four of the seven questions are about satisfaction, worry, how others see it and daytime effects, so the score rises when sleep has become a source of stress.

This reflects how insomnia often works. A run of bad nights, often during a stressful time, leaves people worried about the next one. They go to bed early to catch up, lie awake trying to sleep, check the clock and start to dread bedtime. The worry and effort keep the mind alert, and the problem carries on long after the original stress has gone. Psychologist Arthur Spielman described this in the 1980s as the 3P model: something makes you prone to poor sleep, something sets it off, and habits and worries keep it going.

If your score feels high for the number of hours you get, it may reflect the worry and daytime effects that insomnia treatment addresses. The post on why sleep tips fall short explains what keeps insomnia going and why the usual advice doesn’t reach it.

What helps after a moderate or high ISI score?

For long-lasting insomnia, the usual first recommendation is cognitive behavioural therapy for insomnia, or CBT-I. The American College of Physicians recommended it in 2016 as the first treatment for chronic insomnia in adults, ahead of sleeping pills, and many other guidelines say the same. It’s a short, structured programme, usually between four and eight sessions, and is available with a therapist, in groups or as an online course.

CBT-I works on the habits and thoughts that keep insomnia going rather than on tips. It usually includes:

• Time in bed: matching it to real sleep, so the bed stops being a place where you lie awake.
• Leaving bed when awake: getting up when you can’t sleep and going back to bed when sleepy, so the bed becomes linked with sleep again.
• Sleep worries: working with fears such as one bad night ruining tomorrow.
• A sleep diary: to see the real pattern rather than the remembered one.

These steps are best done with guidance, because some of them make you sleepier for the first week or two. A doctor can tell you how to get CBT-I where you live and talk through other treatment options.

In the meantime, a few things help most people: a steady wake-up time, every day; some daylight in the morning; and a calm wind-down before bed. Slow breathing can make that wind-down easier, and the post on the 4-7-8 breathing pattern describes one simple method. If a racing mind is what keeps you up, the section on night-time worry in breaking an overthinking loop may help.

What else is worth checking alongside your ISI score?

If you want a broader view than lying awake and how much it bothers you, the Pittsburgh Sleep Quality Index looks at the past month of nights in seven parts, including hours slept, how much of your time in bed you spend asleep and what wakes you. The sleep quality test uses it, and the explanation of the seven PSQI components shows how to read them.

If your mood has been low as well, or you’ve lost interest in things you usually enjoy, that’s worth checking too. Poor sleep and low mood feed each other, and a doctor will want to know about both.

How often should you retake the ISI?

Every two weeks or so works well, because the questions ask about the last two weeks. The ISI was designed partly to track treatment, so it’s good at showing change.

Write down your score with the date and a line about what’s been going on. If you start CBT-I or change your routine, the trend tells you more than any single number. Scores often fall in steps rather than smoothly, and a few rough nights don’t undo progress. A score that keeps creeping up, even within the same range, is a sign to get support rather than wait.

If you’d like to see where you are now, or compare with last time, the two-minute insomnia check gives you your ISI score and what it means.