ADHD and always tired? What sleep studies show

Is ADHD linked with being always tired? Studies of adults suggest it can be. Adults diagnosed with ADHD report more daytime sleepiness and poorer sleep, and adults with more ADHD symptoms more often report short or very long nights. These are links, not proof of cause, and tiredness that won't lift is worth raising with a clinician.

ADHD and always tired: what do studies of adults show?

A review pooled 13 studies comparing adults diagnosed with ADHD against adults without it (Díaz-Román, 2018). The people studied were mostly young to middle-aged adults, with average ages of roughly 19 to 40 across the studies.

When adults rated their own sleep, those with ADHD differed on most of the measures. They reported waking more often in the night, lower sleep quality, more general sleep problems and more sleepiness during the day. The gap in daytime sleepiness was a clear one, not a marginal one. They also reported taking longer to drop off, which is a separate question with its own article: can't fall asleep with ADHD, even when tired?

Two things did not differ. Adults with ADHD didn't report sleeping for fewer hours, and they didn't rate their sleep as less refreshing. So in this review, more daytime sleepiness didn't come with shorter reported nights.

The picture also changed with the way sleep was measured. Movement trackers showed two differences: people with ADHD took longer to fall asleep, and their sleep was less efficient. Overnight sleep recordings showed no differences on the measures that could be combined. An unanswered question isn't a settled negative: the studies couldn't yet show what sits underneath the complaints.

The review had real limits. Some measures rested on only a few studies, groups weren't always well matched, other conditions weren't always accounted for, and overnight recordings covered only one or two nights. The authors say sleep complaints should be asked about routinely when adults are assessed for ADHD, and that more research is needed to learn whether they reflect measurable changes in sleep.

Short nights, or very long ones?

A large Dutch study looked at sleep length in the general population rather than in a clinic (Wynchank, 2018). It surveyed 4,618 adults aged 23 to 70. Each person filled in a short questionnaire about ADHD symptoms. Nobody was diagnosed; people were grouped by how many symptoms they reported: none, a few, or enough to be clinically relevant.

Those with clinically relevant symptoms were more likely to report short nights, and more likely to report very long ones. They were also more likely to report significant insomnia symptoms. The pattern ran in steps. The more symptoms people reported, the more likely they were to report short or very long nights.

That pattern held up after the researchers accounted for age and other background factors, lifestyle, physical health, and mood, anxiety and substance use problems. So it wasn't simply explained by those other factors.

The two kinds of symptoms behaved a little differently. Trouble paying attention was linked with both short and long sleep. Hyperactivity symptoms were linked with short sleep but not with long sleep.

There are good reasons for caution here. This was a single snapshot in time, so it can't show which comes first: symptoms leading to poor sleep, poor sleep feeding symptoms, or something else driving both. Everything, including sleep length, was self-reported. The link with very long sleep was also imprecise.

This finding sits uneasily beside a review of studies in adults diagnosed with ADHD, which found no difference in how long they reported sleeping (Díaz-Román, 2018). The two asked different questions of different groups, so neither cancels the other.

Sleeping but still not feeling rested?

A study of 1,240 Japanese workers in regular staff jobs, all university graduates aged 20 to 69, looked at ADHD traits in people who weren't patients (Suzuki, 2023). Each person rated their own traits on a short questionnaire, and answered questions about their work, habits and sleep.

Higher ADHD trait scores were linked with saying they didn't get enough rest from their sleep. That link held after the researchers accounted for everything else they measured, including sex, age, income and working hours.

Sleep length told a different story. Shorter sleep was linked with higher scores at first, but the link faded once those other factors were taken into account. In this group, feeling unrested held up better than the number of hours slept.

The authors note their own limits. An online survey may have drawn people who are more at ease online, the questionnaire was an older version that is less accurate, and self-ratings may understate traits. They say the results should be checked using proper clinical interviews.

A review of studies in adults diagnosed with ADHD found more daytime sleepiness and no difference in reported sleep length, but it also found no difference in how refreshing people rated their sleep (Díaz-Román, 2018). So on feeling rested, the two don't line up neatly. For more on daily rhythms and habits, see late nights? ADHD body clock and sleep habits.

Try this today: write a sentence or two about how sleepy you feel during the day and how rested you feel after sleeping, so it's ready to raise with a clinician.

The Japanese survey and the studies in the review each looked at people at one point in time, so they show links, not causes. None of this can tell you why you, personally, feel tired. If tiredness lasts, raise it with a clinician: only a clinician can diagnose or advise on your own situation.