Is Insomnia a Hybrid State?

Some research suggests that insomnia is a hybrid state, when the brain is neither fully asleep nor fully awake.

Now there’s new evidence for this claim. A new study suggests that insomniacs’ inability to quiet the brain at night is linked to pockets of activity that show up in PET scans while the rest of the brain is asleep.

pet scanSome research suggests that insomnia is a hybrid state, when the brain is neither fully asleep nor fully awake.

Now there’s new evidence for this claim. A University of Pittsburgh study in the October issue of the journal Sleep suggests that insomniacs’ inability to quiet the brain at night is linked to pockets of activity that show up in PET scans while the rest of the brain is asleep.

I was thinking about the implications of this when I went to bed last night. Strange as it may sound, I think it may actually have helped me fall asleep. More about this following news of the study:

Glucose Metabolism During Sleep and Wake

Information processing and thinking require energy. So lots of glucose gets metabolized in the brain during the daytime. Much less glucose is metabolized at night, when the brain is fairly quiet.

The Pitt researchers wanted to assess metabolic activity in the brains of people with and without insomnia to see if there were differences at night and during the daytime. PET scans can measure the rate of metabolic activity occurring in different regions of the brain and render the information in images. So the researchers screened two groups of participants—44 insomniacs and 40 good sleepers—and administered PET scans when they were sleeping and after they woke up.

Summarizing the study results, Daniel Buysse, co-author and professor of psychiatry at the University of Pittsburgh, was quoted in, saying, “What we found is that the people with insomnia have regions of their brain that seem to not shut off as completely when they’re asleep.”

Pitt researchers have been pursuing this line of research for over a decade now. In 2004, results of their first (smaller) neuroimaging study of insomniacs and good sleepers were published, showing similar results.

Regions of Activity and Inactivity in the New Study

Which brain regions were unusually active during sleep? Compared with images of good sleeper brains, the images of insomniacs’ brains during sleep showed significantly higher metabolic activity in 3 key regions associated with

  • Thinking
  • Memory and self-reflection
  • Affect, or mood

This fits pretty neatly with the experience of insomnia, when at night the mind just doesn’t seem to be able to turn itself off. How familiar are thoughts like these: Can I meet my deadline tomorrow? It’s depressing that I handled the presentation so badly. What are they thinking about me now?

Just as interesting was the finding that these same regions of the brain were underactive in insomniacs after they woke up in the morning.

Ever have trouble hauling yourself out of bed? concentrating on your work? feeling low and out of sorts after a bad night’s sleep? Daytime symptoms of insomnia—lack of stamina, trouble thinking, moodiness—may also correspond to the level of metabolic activity occurring in various regions of the brain.

How I Fell Asleep Last Night

When the midnight train whistle sounded I was still engrossed in a novel. But I finally lay down to an internal dialog with myself as I waited to fall asleep:

How’s the spy in the novel going to get back to Viet Nam?

He’s already writing his memoirs in a 3- by 5-foot prison cell. It could get grisly. Bad choice for bedtime reading!

I forgot to read the election news.

Anything but the election! Get back to the character in the book!

I’m too hot. That’s a bad sign.

Throw off a cover, will you!

I might have trouble sleeping.

You’ll fall asleep eventually. You might be partway there.


What if parts of my brain were already asleep? What if at that moment I was experiencing exactly what the neuroimaging studies showed, with parts of my brain already sleeping and other parts resisting sleep? Could I entertain the notion that my brain was halfway released from its burden of consciousness when my mind and senses argued otherwise?

It must have been a comforting proposition. Because after that I was out.

Have you ever had the sensation of being partly awake and partly asleep? What did it feel like?

Author: Lois Maharg, The Savvy Insomniac

Lois Maharg has worked with language for many years. She taught ESL, coauthored two textbooks, and then became a reporter, writing about health, education, government, Latino affairs, and food. Her lifelong struggle with insomnia and interest in investigative reporting motivated her to write a book, The Savvy Insomniac: A Personal Journey through Science to Better Sleep. She now freelances as an editor and copy writer at On the Mark Editing.

7 thoughts on “Is Insomnia a Hybrid State?”

  1. Yes absolutely, I know that sensation! I am frequently aware of that exact ‘half state’ you describe. I recognise that my imagination is starting to wander off and dream, yet another alert/awake part of my brain is still able to register that fact.

    Unfortunately sometimes that in itself is enough to wake me up again fully. I do try and see it as a positive and think oh good, I’m dropping off. Other times that recognition can wake me up again fully.

    Very interesting article. Now we just need researchers to find that elusive on/off switch for our cranial computers.


    1. Thanks, Lesley, for reporting on your experiences in the liminal state between waking and sleep.

      One implication of this study is that now that researchers are figuring out which brain regions have trouble tuning consciousness out, they can develop more targeted sleep medications. This can’t come too soon, judging from the numbers of people who read my blog posts on sleeping pills!


  2. This is exactly what I have been experiencing for the last several weeks. I normally go into that half state you speak of fairly quickly – my body will be dead tired and not want to move at all, and my brain will be drifting from thought to though – I will try breathing, and then within a few minutes I’ll forget I’m supposed to be deep breathing and will think weird thoughts, etc – however, the entire time, my brain is aware. I swear sometimes I even register the fact that I’m in deeper sleep. “Oh, I must be in stage 2 sleep. My breathing is deep and rhythmic, my body is so still…”. Sometimes that wakes me up, just thinking it, sometimes I stay there.

    The challenging part for me is a lot of the recommendations (CBT, specifically) says to get out of bed after 15-20 minutes of not falling asleep – but when I’m in that half state – I am getting rest, and I feel “waking” myself out of it resets the process and robs me of rest. I also feel like it must be restful because one night I never fell asleep at all but had lots of periods where 30 minutes or an hour would go by with me in that half state, and (while I was rather buzzy and tired), I made it through the day OK. I doubt this would have happened if I truly got no sleep.

    Sometimes I end up drifting off to the thought of “I’m going to stop thinking about what to think about, how to breath, etc. I’m getting rest even if it doesn’t feel like it”. Sometimes that helps – sometimes it doesn’t.


    1. Hi Josh,

      You describe that half-sleep/half-wake state quite well. And your concern about how appropriate CBT-I is for someone in your situation is valid. Should you get out of bed after 15 to 20 minutes if in fact most of your brain is asleep? You’re also correct in your assumption that if you weren’t getting any sleep, you’d have problems getting through the day. But you don’t want to continue with the situation as it is.

      Could you make an appointment with a sleep specialist to talk about your symptoms? The first thing you need is a proper diagnosis in order to know how to proceed. As for how much sleep you’re actually getting, the sleep trackers on the market are not accurate enough to provide the kind of information you need. The only way to know for certain is to undergo an overnight sleep study at a sleep clinic.

      A sleep study might indicate that what you’ve got is paradoxical insomnia ( or some other sleep disorder. If it’s paradoxical insomnia, then some type of practice aimed at shutting down arousal at night might be recommended. A few that come to mind are exercise (, yoga (, and mindfulness meditation (

      Good luck in getting a diagnosis and learning to manage the situation so you get more restful sleep.


  3. It is refreshing to see that this study has backed up what I have been dealing with for years as an insomniac. The fact that the stress of wanting to get everything done keeps us up but then in the morning it is turned off because we are drained from the sleepless night prior. This post reminds correlates with a recent post of mine on what this feels like to be trapped in this vicious cycle. If you’re interested, here is the link:


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