Insomnia and Intelligence: Are Insomniacs Smarter?

There is no good evidence that people with insomnia are more intelligent. Across 48 studies, adults with insomnia scored slightly lower on cognitive tests than good sleepers (an average effect of g = -0.24, roughly 3.6 points if expressed on the IQ scale), and large genetic studies link insomnia to lower, not higher, educational attainment.

The idea of the brilliant insomniac whose mind will not switch off is appealing, but it rests mostly on anecdotes and small, mixed studies of gifted children. This page explains what insomnia is, how it relates to test performance, what the research on bright people's sleep shows, and where to get help.

"Insomnia" means persistent trouble falling asleep, staying asleep or waking too early, despite having the chance to sleep, together with daytime consequences such as fatigue or poor concentration. In a review of more than 50 population surveys, Maurice Ohayon found that about a third of adults report at least one insomnia symptom. When daytime consequences are required, the figure falls to 9% to 15%, and about 6% meet the criteria for an insomnia diagnosis.

Insomnia overlaps with, but differs from, two topics we cover elsewhere. Short sleep forced by work, study or a newborn is sleep deprivation, and our article on how sleep affects IQ and cognitive performance covers that research. A preference for staying up late is a matter of chronotype, which our page on IQ and night owls discusses. Breathing-related sleep disruption is different again, and is covered in our article on IQ and sleep apnea.

Two meta-analyses have compared people with insomnia with normal sleepers on standardized cognitive tests.

• Fortier-Brochu and colleagues (2012): Pooling 24 studies with 639 people with insomnia and 558 normal sleepers, they found small to moderate deficits on episodic memory (effect size -0.51), problem solving (-0.42), manipulating information in working memory (-0.42) and holding information in working memory (-0.22). There were no significant differences on measures of general cognitive function, verbal functions, perceptual and psychomotor processes, or most kinds of attention.

• Wardle-Pinkston, Slavish and Taylor (2019): With 48 studies and 4,539 participants, insomnia was associated with poorer overall cognitive performance (g = -0.24). The largest deficits were in working memory manipulation (g = -0.52) and problem solving (g = -0.39). People with insomnia also rated their own thinking as worse (g = -0.35). About 44% of the studies did not use formal diagnostic criteria for insomnia, and the cognitive tests varied widely.

To put g = -0.24 in context, an effect of a quarter of a standard deviation corresponds to about 3.6 points on a scale with a standard deviation of 15. That conversion is only a rough guide, because most of these studies used specific tasks such as memory or reasoning tests, and the earlier meta-analysis found no significant difference on measures of general cognitive function. The research also cannot say which way the influence runs. Poor sleep may impair memory and reasoning, but the depression and other mental health problems that often accompany insomnia can affect test performance too.

The best large-scale evidence points the other way. In a genome-wide study of 113,006 people, Anke Hammerschlag and colleagues found that the genetic influences on insomnia complaints were negatively correlated with those on educational attainment (r = -.34). A much larger genome-wide study of 1,331,010 people by Philip Jansen and colleagues used Mendelian randomization, a method that uses genetic variants as natural experiments, and found that educational attainment had a protective effect against insomnia. Education is not the same as intelligence, but the two are strongly linked, so these results make a hidden advantage for insomniacs unlikely.

Studies of gifted children are small and do not agree:

• Actigraphy study, 124 children: Laurianne Bastien and colleagues compared 62 gifted children with 62 typically developing children matched on age and sex. The gifted group had lower sleep efficiency, more time awake after falling asleep and more night-to-night variability, and their parents reported more clinically significant sleep problems. Giftedness was defined with Renzulli's three-factor model, which includes creativity and task commitment as well as ability, so the group was not selected on IQ alone.

• Questionnaire and diary study, 58 children: Joseph Piro and colleagues compared 35 gifted and 23 non-gifted students aged 8 to 12. The gifted students trended toward more sleep disturbance, but there were no significant differences in bedtime, hours slept or sleeping problems.

Research on ordinary children is just as mixed. In 60 healthy 7- to 11-year-olds, Anja Geiger and colleagues found that shorter sleep on weekends went with higher full-scale IQ (r = -.29). In 39 children of the same age, Reut Gruber and colleagues found the opposite: longer habitual sleep went with better perceptual reasoning and overall IQ. Samples this small can easily produce conflicting results, and neither study measured insomnia.

Stories about famous scientists and writers who slept little are memorable, and people who lie awake thinking about ideas may feel that a busy mind is a sign of a bright one. Anecdotes like these are selected because they are striking. Nobody tells stories about the much larger number of people with insomnia who are not famous, or about brilliant people who sleep well.

There is also a measurement problem. Most people never have their sleep or their IQ measured, so beliefs about the two rest on self-description. In the larger meta-analysis above, people with insomnia rated their own thinking as clearly worse than good sleepers did, which is a reminder that how we feel about our sleep and our thinking is not the same as a measured score.

Insomnia is a common and treatable condition. In 2021 the American Academy of Sleep Medicine issued a strong recommendation that clinicians use multicomponent "cognitive behavioral therapy for insomnia" (CBT-I) to treat chronic insomnia disorder in adults. The World Sleep Society endorsed that recommendation in 2023, noted that sleep hygiene education on its own lacks evidence as a single therapy, and pointed out that there are not enough trained therapists in many parts of the world.

If insomnia is affecting your days, the place to start is a primary care doctor, who can look for medical, psychiatric or medication-related causes and refer you to a sleep medicine specialist or a psychologist trained in CBT-I. This article describes the research and is not a substitute for that assessment.

Treating insomnia has not yet been shown to raise cognitive test scores. In a 2018 systematic review of 18 studies with 923 people, Vanessa Herbert and colleagues found preliminary evidence that CBT-I improved how well people felt they were thinking, but only four studies used objective cognitive tests, too few to draw conclusions.

No. People with insomnia perform slightly worse on cognitive tests on average (g = -0.24 across 48 studies), and genetic studies link insomnia to lower educational attainment.

Insomnia is linked to small deficits in memory, working memory and problem solving, but one meta-analysis found no significant difference on measures of general cognitive function. There is no evidence that it permanently lowers IQ.

Possibly, but the evidence is thin. One actigraphy study of 62 gifted children found more broken sleep, while another small study found no significant differences.

No study we found shows that. Insomnia has been linked much more consistently with depression than with high ability.

Professional guidelines recommend cognitive behavioral therapy for insomnia (CBT-I) as the first treatment for chronic insomnia in adults. A primary care doctor or sleep medicine specialist can assess the problem and arrange it.

Insomnia is not a sign of high intelligence. People with insomnia do slightly worse on cognitive tests, especially memory and working memory tasks, genetic studies tie insomnia to lower educational attainment, and research on gifted children's sleep is too small and too mixed to support the myth. If you are struggling with sleep, see a doctor about CBT-I. If you are curious about your reasoning ability, test on a well-rested day and take the RIOT IQ test.

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Hero image: Digital clock 3.00 AM, by PEAK99, CC BY 3.0. Via Wikimedia Commons.