Sleep Condition Indicator (SCI)

Assess Your Sleep with the Sleep Condition Indicator (SCI)

Poor sleep can affect your day-to-day life, and the Sleep Condition Indicator (SCI) is a helpful tool to understand it better. Developed by sleep experts, this straightforward assessment screens for insomnia by looking at your sleep over the past month. As a Sydney psychologist who works with sleep issues, I find it a useful starting point. You can try the test below or read on for more information at your own pace.

What is the Sleep Condition Indicator (SCI)

The Sleep Condition Indicator (SCI) is a questionnaire designed to give you a clear picture of your sleep health and check for signs of insomnia. Created by Professor Colin Espie and his team, it includes eight questions about your sleep over the past month, such as how long it takes to fall asleep, how often you wake up, and how it affects your daily routine. Your answers produce a score from 0 to 32, where higher numbers suggest better sleep. It’s widely used by health professionals and researchers to spot potential insomnia issues, making it a reliable resource for anyone curious about their sleep.

Why Use the Sleep Condition Indicator

The Sleep Condition Indicator (SCI) is a practical tool to assess your sleep, especially since insomnia is more common than you might think. Studies show that 10–12% of people meet the criteria for insomnia disorder, with up to 40% experiencing some sleep challenges, which can lead to tiredness, irritability, or low mood. In the past, health professionals often missed these issues due to a lack of simple screening methods. The SCI addresses this with:

Ease of Use: It takes just 2–3 minutes to complete, fitting easily into a busy day.
Clear Feedback: The score helps you see if insomnia might be a concern, offering a starting point for reflection.
Support for Understanding: As a psychologist in Sydney, I use the SCI alongside tools like sleep diaries to better understand sleep patterns and guide insomnia treatment when needed.
It’s a gentle way to explore your sleep, whether you’re curious on your own or considering a conversation with a professional.

Take the Sleep Condition Indicator (SCI)

Understanding Your SCI Results

Once you’ve completed the Sleep Condition Indicator (SCI), you’ll receive a score between 0 and 32 that reflects your sleep health over the past month. Here’s what it means: a higher score indicates better sleep, while a lower score suggests potential insomnia. Specifically, scores below 16 often point to sleep difficulties that might need attention, with scores below 8 indicating more significant concerns. For example, a score of 12 might mean you’re struggling with falling asleep or staying asleep more nights than not, which could be a sign of insomnia disorder. This score isn’t a diagnosis on its own—it’s a starting point to understand your sleep better. As a Sydney psychologist, I often use these results alongside other tools, like sleep diaries, to get a fuller picture of what’s happening. If your score is low, it might be worth exploring further through a session to discuss what’s affecting your sleep and possible next steps.

The Science and Development of the SCI

The Sleep Condition Indicator (SCI) is rooted in solid sleep research, making it a dependable tool for assessing insomnia. Developed in the early 2010s by Professor Colin Espie and his team at the University of Oxford, alongside other sleep experts, it was first published in 2014 to address a clinical need. This need emerged in 2013 when the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5)—a guide used by health professionals to classify mental health conditions, updated with the latest evidence—redefined insomnia as a standalone disorder.

Before DSM-5, insomnia was often viewed through the primary vs. secondary model, where it was seen as a symptom of another issue (e.g., depression or chronic pain) rather than a distinct problem. This approach was limited because it often led to insomnia being ignored if the main condition was treated, even though insomnia can exist on its own, worsen other issues, or even come first. The DSM-5 changed this by setting clear criteria—difficulty falling or staying asleep at least three nights a week for three months, causing distress or impairment—encouraging better recognition and management of insomnia.

To meet this need, Espie’s team created the SCI as a brief, DSM-5-aligned questionnaire that general practitioners could use easily. Its eight questions—covering sleep onset, staying asleep, sleep quality, frequency, duration, and daytime impacts—were designed using current insomnia research and DSM-5 guidelines. Before the SCI, tools like the Pittsburgh Sleep Quality Index (PSQI) focused broadly on sleep quality without insomnia specificity, and the Insomnia Severity Index (ISI) relied on older DSM-IV criteria. The SCI filled this gap with a practical design.

Validity and Reliability of the SCI

The Sleep Condition Indicator (SCI) has been thoroughly tested to ensure it’s a tool you can trust. In research, we look at two key qualities: reliability and validity. Reliability means the SCI gives consistent results—like a thermometer that always reads your temperature correctly. Validity means it measures what it’s designed to—in this case, how severe someone’s insomnia is—not something unrelated. Let’s break down why the SCI delivers on both.

Reliability: Consistency You Can Count On

The SCI’s questions are designed to work together, producing steady results. In early studies, researchers measured this with a statistic called Cronbach’s alpha, which shows how well the questions align. They found scores of 0.86 or higher—excellent by research standards. A Swedish study later reported an even stronger 0.91. What does this mean? People with sleep problems tend to answer the questions in a way that consistently reflects their struggles, while those who sleep well score high across the board. This tells us the SCI is dependable—its results don’t flip-flop randomly.

Validity: Measuring Insomnia, Not Something Else

The SCI accurately captures insomnia severity, and we know this because it lines up with other trusted sleep tools. For example, studies compared it to the Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI)—both widely used questionnaires. On the SCI, a higher score means better sleep; on the ISI and PSQI, a higher score means worse sleep. Sure enough, people with low SCI scores (poor sleep) also had high ISI and PSQI scores (poor sleep). This match confirms the SCI is measuring insomnia as it should.

Importantly, the SCI doesn’t overlap too much with tools for depression or anxiety. Studies found only a weak connection between SCI scores and those conditions. This is a good thing—it shows the SCI zeroes in on sleep problems specifically, not just general distress, even though insomnia and mood issues often go hand in hand.

Covering the Full Picture of Insomnia

The SCI’s questions address both nighttime troubles (like difficulty falling asleep) and daytime effects (like feeling tired or moody), which are core features of insomnia according to the DSM-5, the standard guide for diagnosing mental health conditions. This makes it a complete snapshot of the disorder. It’s also sensitive to change—after treatments like cognitive-behavioral therapy, SCI scores rise when sleep improves and drop if it worsens. This makes it a practical tool for tracking progress over time, not just assessing sleep at one moment.

Tested Across Cultures and Conditions

Since its development, the SCI has proven itself in diverse settings. Translated into languages like Swedish and Indonesian (with slight tweaks for cultural fit), it performs just as well—Swedish studies, for instance, showed a strong match with the ISI. A 2021 study even validated it for people with Parkinson’s disease, a group prone to sleep issues, recommending it for both clinical care and research. Built on data from over 30,000 participants and backed by ongoing studies, the SCI is a robust, adaptable tool for understanding sleep health and guiding insomnia treatment.

Comparing the SCI with Other Sleep Measures

The Sleep Condition Indicator (SCI) is one of several tools used to assess sleep, each with its own strengths. Comparing it to other measures can help you understand its role in exploring insomnia:

SCI: This 8-question tool takes 2–3 minutes to complete and scores from 0 to 32, with scores below 16 suggesting possible insomnia. It focuses on sleep quality and insomnia symptoms over the past month, making it a quick and user-friendly option for initial screening.
Insomnia Severity Index (ISI): The ISI has 7 questions, takes about 5 minutes, and scores from 0 to 28, where scores above 14 indicate insomnia. It dives deeper into the severity and impact of insomnia, such as how much it interferes with daily life, but it’s based on older criteria (from before 2013) and takes slightly longer to complete.
Pittsburgh Sleep Quality Index (PSQI): The PSQI uses 19 questions, takes 5–10 minutes, and scores from 0 to 21, with scores above 5 suggesting poor sleep. It looks at overall sleep quality, including habits like bedtime routines, but isn’t specific to insomnia, making it broader but less focused on insomnia symptoms.
Athens Insomnia Scale (AIS): The AIS has 8 questions, takes 3–5 minutes, and scores from 0 to 24, with scores above 6 indicating insomnia. It’s similar to the SCI in length but emphasizes the intensity of insomnia symptoms, like how severe the sleep difficulties feel, rather than overall sleep quality.
In summary, the SCI stands out for being quick and aligned with modern insomnia criteria, making it great for a fast check. The ISI focuses more on severity, the PSQI gives a wider view of sleep habits, and the AIS highlights symptom intensity. In my practice, I often pair the SCI with tools like sleep diaries to get a fuller picture of your sleep as part of insomnia treatment.

Limitations and Criticisms of the SCI

Like any tool, the Sleep Condition Indicator (SCI) has its limits, and it’s helpful to understand these when looking at your results:

Not a Full Diagnosis: The SCI is a screening tool, not a complete check for insomnia. It doesn’t cover every detail needed for a full diagnosis. For example, one rule for insomnia in the DSM-5 (a guide health professionals use to identify mental health conditions) is that sleep problems happen even when you have enough time to sleep—the SCI doesn’t ask this directly. It also can’t tell if something else, like another sleep issue or substance use, is causing the problem. A low score means insomnia is possible, but a health professional would need to ask more questions to confirm.
Some Symptoms Missed: The SCI’s eight questions cover a lot, but not everything. For instance, it doesn’t directly ask about waking up too early in the morning and being unable to fall back asleep, which some people with insomnia experience. It does ask about waking during the night generally, and the creators suggest following up on this to check for early waking, but it’s not a specific question. It also doesn’t look at differences between weekdays and weekends or how much your sleep varies, focusing instead on a typical night.
Based on Your Perception: The SCI relies on what you report about your sleep, which makes sense because insomnia is about how you feel. But this means it depends on your memory, and sometimes people might overestimate or underestimate things—like thinking they got “no sleep” on a tough night when they actually slept a few hours. This isn’t usually a big problem, but it means the SCI reflects how you perceive your sleep, not exact minutes, which a sleep tracker might measure differently.
Other Possible Causes: A low SCI score shows poor sleep that looks like insomnia, but other issues could be the cause. For example, someone with sleep apnea—a breathing problem during sleep—might report waking often and feeling tired, leading to a low SCI score, even though the issue isn’t insomnia. The SCI can’t tell the difference, so a health professional would need to explore other possibilities, like sleep apnea or a mismatched sleep schedule.
Who Took the Test: Some researchers note that the SCI was first tested mostly with people who took it online, often because they already had sleep concerns. In those early studies, over half of the participants had signs of insomnia, which might make the SCI seem better at spotting insomnia than it would in a more varied group. The researchers did compare people with and without sleep issues to check its accuracy, but testing in more diverse groups—like people who aren’t already worried about sleep—can help confirm how well it works for everyone.
Even with these limits, the SCI is a helpful tool when used as part of a bigger picture. Its strengths—like being quick, matching modern insomnia criteria, and having strong research support—make it valuable, especially when paired with follow-up questions or tools like sleep diaries in insomnia treatment. Understanding what the SCI can and can’t do ensures it’s used thoughtfully.

FAQ for the Sleep Condition Indicator

How long does the SCI take to complete?
It takes about 2–3 minutes to answer the eight questions, making it a quick way to check your sleep health.
Is the SCI a diagnosis for insomnia?
No, the SCI is a screening tool, not a diagnosis. It helps identify possible insomnia, but a health professional would need to assess further to confirm insomnia disorder.
Can I retake the SCI to track my sleep over time?
Yes, you can retake the SCI as often as you’d like. It’s a good way to see if your sleep improves, especially if you’re working on insomnia treatment or using tools like sleep diaries .
What if I don’t remember my sleep patterns exactly?
That’s okay—just answer based on what you recall about your typical sleep over the past month. The SCI focuses on your overall experience, so small memory gaps won’t affect the results much.

Explore More Insomnia and Sleep Tools

Investigate other validated measures to assess insomnia, sleep quality, sleep hygiene, and factors like daytime sleepiness or beliefs about sleep. Track patterns with our sleep diary or visit our assessment hub for a full overview of insomnia assessment.

Insomnia Severity Index (ISI) – Gold standard self-report tool for insomnia severity over two weeks.
Pittsburgh Sleep Quality Index (PSQI) – Assesses overall sleep quality and disturbances over a month.
Athens Insomnia Scale (AIS) – Broad sleep quality, not just insomnia.
Sleep Condition Indicator (SCI) – Screens insomnia per DSM-5 with a focus on sleep satisfaction.
Epworth Sleepiness Scale (ESS) – Guages daytime sleepiness across eight everyday situations.
Sleep Hygiene Index (SHI) – Identifies sleep-disruptive habits and behaviours affecting rest.
Dysfunctional Beliefs and Attitudes about Sleep (DBAS-16) – Probes unhelpful beliefs influencing sleep difficulties.
Pre-Sleep Arousal Scale (PSAS) – Measures cognitive and physical arousal before bedtime.

Assessment Hub: Central hub for all sleep and insomnia measures.
Sleep Diary: Records daily sleep habits for personalised insights.

References for the Sleep Condition Indicator (SCI)

Espie, C. A., Kyle, S. D., Hames, P., Gardani, M., Fleming, L., & Cape, J. (2014). The Sleep Condition Indicator: A clinical screening tool to evaluate insomnia disorder. BMJ Open, 4(3), e004183. https://doi.org/10.1136/bmjopen-2013-004183

This study introduces the Sleep Condition Indicator (SCI), an eight-item questionnaire designed to assess insomnia disorder in line with DSM-5 criteria. The authors detail the development process and validate the SCI’s effectiveness in clinical settings, demonstrating its reliability and validity.

McLaren, D. M., Evans, J., Baylan, S., & Gardani, M. (2024). Assessing insomnia after stroke: A diagnostic validation of the Sleep Condition Indicator. Neurology Open, 6(2), e000768. https://doi.org/10.1136/bmjno-2024-000768

This research evaluates the diagnostic accuracy of the SCI in identifying insomnia among stroke survivors. The findings confirm the SCI’s validity in this population, suggesting a modified threshold score for optimal sensitivity and specificity.

Espie, C. A., Kyle, S. D., Hames, P., Gardani, M., Fleming, L., & Cape, J. (2014). The Sleep Condition Indicator: A clinical screening tool to evaluate insomnia disorder. University of Strathclyde. Retrieved from https://strathprints.strath.ac.uk/59473/

This publication provides an overview of the SCI, emphasizing its development and application in clinical settings for evaluating insomnia disorder.

Espie, C. A., Kyle, S. D., Hames, P., Gardani, M., Fleming, L., & Cape, J. (2014). The Sleep Condition Indicator: A clinical screening tool to evaluate insomnia disorder. University of Manchester. Retrieved from https://research.manchester.ac.uk/en/publications/the-sleep-condition-indicator-a-clinical-screening-tool-to-evalua

This resource outlines the development and validation of the SCI, highlighting its role as a screening tool for insomnia disorder in clinical practice.

Espie, C. A., Kyle, S. D., Hames, P., Gardani, M., Fleming, L., & Cape, J. (2014). The Sleep Condition Indicator: A clinical screening tool to evaluate insomnia disorder. Nuffield Department of Clinical Neurosciences, University of Oxford. Retrieved from https://www.ndcn.ox.ac.uk/publications/457969ndcn.ox.ac.uk+1bmjopen.bmj.com+1

This publication discusses the SCI as a clinical tool for assessing insomnia disorder, detailing its validation and potential applications in healthcare.