Insomnia Test: Insomnia Severity Index (ISI)
Poor sleep affects everything: your concentration, memory, mood, energy, and ability to cope with daily demands. The Insomnia Severity Index (ISI) is one of the most widely used clinical tools for measuring insomnia severity and its impact on your life. Developed by Professor Charles Morin and validated across large community and clinical samples, it takes just two minutes and covers the past two weeks.
If poor sleep is affecting your cognitive function, you may also find our Fatigue Severity Scale useful, as fatigue and insomnia are closely linked but distinct problems.
Take the Insomnia Severity Index
Insomnia Severity Index (ISI)
7 questions about your sleep · Takes 2 minutes
Instructions: For each question, select the option that best describes your sleep over the last two weeks.
Your answers are not stored or transmitted. Everything runs in your browser.
No Clinically Significant Insomnia
Subthreshold Insomnia
Moderate Insomnia
Severe Insomnia
Better Sleep Starts With Less on Your Mind
Racing thoughts and unfinished mental to-do lists are among the most common barriers to falling asleep. Recallify helps you offload those thoughts before bed through voice capture, automatic task extraction, and smart reminders for the morning.
What Does the ISI Measure?
The ISI consists of seven questions covering three dimensions of insomnia: the severity of your sleep difficulties (falling asleep, staying asleep, waking too early), your satisfaction with your current sleep pattern, and the impact of poor sleep on your daily functioning, including how noticeable it is to others, how much it worries you, and how much it interferes with your day.
A 2011 validation study of nearly 1,000 community participants found that the ISI has excellent internal consistency (Cronbach’s alpha of 0.90) and that a cut-off score of 10 achieved 86% sensitivity and 88% specificity for detecting insomnia cases.
How Is the ISI Scored?
Each item is scored 0 to 4, giving a total between 0 and 28. The established bands are: 0 to 7 (no clinically significant insomnia), 8 to 14 (subthreshold insomnia), 15 to 21 (moderate clinical insomnia), and 22 to 28 (severe clinical insomnia). Scores of 15 or above have been correlated with receiving a clinical insomnia diagnosis in research settings. The ISI is also useful for tracking change over time, for example during treatment.
Why Sleep Matters for Cognitive Health
Sleep is not optional for cognitive function. It is when your brain consolidates memories, clears metabolic waste, and restores the resources needed for attention, decision-making, and emotional regulation. Chronic insomnia impairs all of these processes. For people living with ADHD, brain injuries, MS, or other cognitive challenges, poor sleep compounds existing difficulties and can make strategies that otherwise work feel ineffective. Understanding the severity of your sleep problem is the first step toward addressing it.
How Recallify Helps When Sleep Is Poor
One of the most common barriers to falling asleep is a racing mind full of unfinished tasks and things you are trying not to forget. Recallify helps you offload those thoughts before bed. A quick voice recording captures everything on your mind, and the app automatically extracts tasks and sets reminders for the morning so you can let go. When you trust that nothing will be lost, it becomes easier to switch off.
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Frequently Asked Questions
Is this a diagnosis of insomnia?
No. The ISI is a screening tool that measures the severity and impact of insomnia symptoms. A formal diagnosis of insomnia disorder requires a clinical assessment, which may include a sleep diary, discussion of your medical history, and sometimes a sleep study. If your score is 15 or above, we would encourage you to speak with your GP.
What is a normal ISI score?
A score of 0 to 7 indicates no clinically significant insomnia. Scores of 8 to 14 suggest subthreshold insomnia (some sleep difficulties but below the clinical threshold). Scores of 15 or above indicate clinically meaningful insomnia that warrants professional attention.
What treatment is available for insomnia?
The [NHS recommends cognitive behavioural therapy for insomnia (CBT-I)] as the first-line treatment. CBT-I addresses the thoughts and behaviours that maintain insomnia and has strong evidence behind it. It is available through the NHS, and there are also digital CBT-I programmes. Medication may be considered in some cases but is generally not recommended as a long-term solution.
Can poor sleep make ADHD, brain injury, or MS symptoms worse?
Yes, significantly. Sleep deprivation impairs working memory, attention, and executive function, which are already challenged in these conditions. Treating insomnia often produces noticeable improvements in cognitive function, mood, and daily coping.
How often should I take the ISI?
The ISI asks about the past two weeks. You can repeat it fortnightly to track whether your sleep is improving, especially if you are trying new strategies or receiving treatment.
Are my questionnire answers stored?
No. This tool runs entirely in your browser. No answers or scores are stored, transmitted, or shared