Please make note that the headline for this post should be sung to the tune of “Let’s Talk About Sex” by Salt N’ Pepa, and if you don’t know that song, you’re too young to be here.

Just kidding! This article has no age restriction and I’m glad you’re here! Because today we’re talking circadian rhythm, and all the ways ADHD can disrupt it.

Cir-what-ian Rhythm?

Circadian rhythm is the internal mechanism that controls our ability to sleep and stay awake. It dictates when you’ll be tired, how much sleep you need, when you wake up in the morning, and how groggy or alert you feel throughout the day.

Our circadian rhythm shifts throughout our lives. Babies aren’t born with one, which is why their sleep schedule is so erratic. Toddlers and young children tend to go to bed early and wake up early, whereas teenagers tend to go to bed late and desperately want to sleep in but public schools don’t care.

In adults, the cycles of tiredness and wakefulness vary based on several factors, but most adults require at least 7-9 hours of sleep per night. As we age, we may go to bed earlier and wake up earlier again, or require less sleep.

What Affects It?

Pretty much everything we do. The circadian rhythm is a sensitive system and our habits, brain chemistry, physical condition and lifestyle can disrupt or shift it through:

  • Working late hours or overnight
  • Ingesting caffeine late in the day
  • Having any number of neuropsychological or psychiatric conditions
  • Sleeping on an irregular schedule
  • Stress
  • Medication
  • Alcohol
  • Blindness
  • Exercise
  • Late-night screen time

Let Me Guess, ADHD Too?

I hate to bring the bad news, but yes, ADHD can affect your circadian rhythm in a variety of ways.

Though it’s not a manifestation as part of the DSM-5, difficulty with sleeping and wakefulness occurs in anywhere from 50-80% of adults with ADHD. Most would say they’ve experienced one or more of the below difficulties.

“I Can’t Fall Asleep”

Have you ever been so tired at night that you can’t wait to get to bed, so you lay down and get cozy under the covers, close your eyes, and then suddenly your mind starts racing?

I have! And I’m sure I don’t have to tell you how much it totally sucks!

Turns out this is a very common occurrence amongst those with ADHD. They feel tired enough to go to bed, but as soon as they actually try to sleep, they start thought jumping and it can take anywhere from 30 minutes to a few hours to fall asleep because they can’t mentally relax.

For reference, a “typical” adult should be able to fall asleep within 10 to 20 minutes, and the amount of time it takes to do so is called sleep latency.

Longer sleep latency is often related to insomnia, which can be acute – occurring occasionally and lasting less than a week – or chronic – occurring at least three times per week for three months. Approximately 70% of adults with ADHD experience insomnia, which is significantly higher than in adults without ADHD.

Difficulty falling asleep could also be a sign of delayed sleep phase disorder, which is a disruption in one’s circadian rhythm that causes a person to become tired two or more hours after what could be considered an “appropriate” bedtime.

“I Can’t Stay Asleep”

How often do you wake up in the middle of the night? If your answer is “almost every night”, then we have something in common!

Insomnia doesn’t just refer to difficulty falling asleep – it’s also the term that covers difficulty staying asleep, and this is again a very common problem for people with ADHD.

Waking up in the middle of the night can occur due to a variety of factors:

  • Restless leg syndrome
    • An irresistible urge to move one’s legs or other limbs, which can occur in up to 44% of adults with ADHD
  • Sleep apnea
    • Partial or complete upper airway obstruction (or collapse) that causes irregular patterns or full disruption of breathing
  • Overheating
    • Whether from dehydration, room temperature, anxiety or medication

Waking up in the night can disrupt rapid eye movement (REM) sleep, which many researchers hypothesize may be a critical stage of sleep. Recent studies suggest REM sleep may be partially responsible for our ability to recognize emotions in others and our ability to remain calm in the face of fear. Studies also suggest that dreaming, which occurs most vividly during REM sleep, may have effects on memory and mood.

“I Can’t Wake Up”

“I’ll just snooze my alarm and get a few more minutes”… *Wakes up one hour later panicked and late*

If the above seems familiar, then we’re three for three on shared experiences!

People with ADHD often have difficulty waking up, referred to as sleep inertia, and probably have a pretty familiar relationship with the snooze button.

Interestingly, despite the thorough number of studies on difficulty falling asleep, I found fewer scientific explanations for reasons it can be difficult to wake up. I feel we will need to extrapolate a bit from the information we’ve already reviewed:

  • Grogginess upon waking can occur when a person is abruptly woken from REM sleep
    • This is the last of the four stages of sleep
    • If you wake up multiple times in the night, your REM sleep may be occurring closer to the time your alarm goes off in the morning
  • Grogginess can also occur when the quality of sleep has been bad
    • This is common for people with sleep apnea, or for people who wake up frequently
  • It’s difficult to wake up when you haven’t had enough sleep
    • Most people seriously underestimate how much sleep they need
    • It’s difficult to get the right amount of sleep when you can’t anticipate how long it will take to fall asleep on any given night

“I’m Falling Asleep in Meetings”

Have we made connect four?

If you also have difficulty staying awake through the day – especially in the mid-afternoon – again, it’s not uncommon.

Remember the circadian rhythm? Keep in mind it’s a 24-hour internal clock and it’s responsible not just for making us tired at night, but also occasionally during the day.

Most adults report being tired in the mid- to late afternoon, not just those with ADHD. So, the post-lunch grogginess is very typical, but it may be exaggerated in those with ADHD – likely because of other sleep problems. While it’s normal for you to want to zone out around 2pm, if you feel like you really struggle to keep your eyes open, it could be caused by your general sleeplessness at night.

But many with ADHD may find they are tired other times of the day, and the exhaustion may come on suddenly, even in the middle of an activity. This could be caused by serious under-stimulation. If you’ve ever fallen asleep in a lecture, meeting, or other classroom-type setting, it’s essentially boredom so extreme that you can no longer stay awake – probably compounded by fatigue from poor sleep

But Why Do We Suffer So?

Sadly, I have no easy answer for you.

There are many theories, but no specific cause for the sleeplessness we experience.

It may be a matter of executive dysfunction – our inability to activate ourselves to go to sleep or to stay awake. It may be that difficulty with sleep is just another manifestation of ADHD based on brain structure, and dopamine levels and transmission. Or, it could be caused by time blindness, which is so internalized that even our circadian rhythm is affected by it.

It seems too that there’s a vicious cycle that occurs with ADHD and sleep. ADHD causes problems sleeping, which exacerbates our ADHD manifestations like memory and attention, which stresses us out, which makes it harder to fall asleep because we’re anxious, and so on.

Ready to get better sleep? Head over to Part 2 for some tips on improving your sleep hygiene!


References, in no particular order or citation style:

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