Insomnia may persist even after successful sleep apnea treatmentLet’s say that after years of experiencing insomnia you go in for a sleep study only to find out you have obstructive sleep apnea. Who knew? You’re outfitted with a breathing mask, you wear it as prescribed, and your sleep improves . . . somewhat.

But your insomnia symptoms are persistent, and you don’t have the kind of stamina you’d like during the day. What then?

Insomnia and Sleep Apnea

Insomnia and obstructive sleep apnea (complete or partial reduction of breathing during sleep) are the two most common sleep disorders. Many people have one or the other, and some people have both. According to a new paper published in Sleep Medicine Reviews, 39% to 58% of people diagnosed with sleep apnea also report symptoms of insomnia.

The name for this problem is comorbid insomnia and sleep apnea, or COMISA. Having one of these disorders is bad enough: apnea often results in broken sleep and daytime sleepiness. Insomnia, beyond its negative impact on sleep, can sap your energy and dampen your mood. But the effects of COMISA on sleep quality and daytime functioning are worse.

Two acquaintances of mine—Matt and James—were initially diagnosed with sleep apnea. Their experiences were similar to the one described above: a sleep study, an unexpected diagnosis of sleep apnea, and nightly use of a CPAP machine (the machine with the pressurized breathing mask). But despite receiving treatment for sleep apnea, their trouble falling asleep and lack of daytime stamina persisted. Neither one was satisfied that his sleep problem had been fully addressed.

A Complicated Affair

The relationship between sleep apnea and insomnia is not simple, according to a summary of research presented at the 23rd Congress of the European Sleep Research Society last fall. Some studies suggest that insomnia should be thought of as secondary to sleep apnea. Frequent awakenings in the middle of the night (also called middle insomnia) are often prompted by interruptions in breathing. In such cases treatment for the apnea—with an appropriate CPAP device—can correct both the breathing problem and the nighttime awakenings, resulting in continuous breathing and consolidated sleep. Voilà, the two problems are solved.

In other instances, co-occurring insomnia and sleep apnea appear to be distinct disorders requiring separate interventions to turn the situation around.

A Study Involving Insomnia Subtypes

Erla Bjornsdottir and colleagues conducted a 2-year prospective study in which they followed over 700 sleep apnea patients undergoing CPAP treatment to assess how their insomnia symptoms changed over time. Changes in participants’ insomnia symptoms varied according to the subtype of insomnia they had:

  • In participants with middle insomnia, CPAP treatment significantly decreased their middle-of-the-night awakenings. This is further evidence that in people with COMISA, symptoms of middle insomnia are probably a consequence of sleep disordered breathing. Treatment with CPAP alone may alleviate both problems.
  • In participants with initial insomnia (trouble getting to sleep at the beginning of the night), CPAP treatment did nothing to relieve their insomnia symptoms. This suggests that disordered breathing is not the cause of the initial insomnia, and that people who have it should also be treated for insomnia (with cognitive behavioral therapy for insomnia—CBT-I—for instance).
  • In participants with late insomnia (early morning awakenings), CPAP treatment did not lessen their early awakenings. This suggests that late insomnia in people with COMISA is not due to disordered breathing and should be addressed separately.

Now back to Matt and James: Matt, while using his CPAP machine, went through CBT-I hoping to overcome his residual insomnia. Overall he was satisfied with the result. Read more about his story in chapter 8 of The Savvy Insomniac: A Personal Journey through Science to Better Sleep.

As for James, the last I knew of him, he was sliding a bit in his use of the CPAP. But he was talking about returning to a sleep specialist to get more help. I hope he made that appointment.

If you have a CPAP machine, how has your sleep and quality of life changed since you started using it?

Posted by 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.


  1. I saw this article in Sleep Review and the research findings make a lot of sense to me. Sleep apnea usually shows as repetitive, relatively brief arousals at night resulting in daytime sleepiness. Seems logical to me that PAP would effectively treat that respiratory pattern and result in less of a middle “sleep maintenance” Insomnia complaint. And it seems logical that someone who experiences sleep-onset or early awakening insomnia and sleep apnea might not realize as much insomnia relief from PAP. An insightful round of Q/A by a sleep specialist can help point someone with COMISA in the right direction!



  2. Hi Michael,

    The findings concerning the response of initial, middle, and late insomnia to treatment with PAP seem logical to me, too. Yet as far as I know the Bjornsdottir study was the first to actually produce results confirming what you and others may already have observed in the sleep lab.

    In any case COMISA is, as you point out, a problem that needs attention from a sleep specialist. Thanks for the comment!



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