Two sleep problems that sound like opposites turn out to travel together far more often than chance, and the combination has a name most people have never encountered: COMISA — comorbid insomnia and obstructive sleep apnea.
Between 30% and 50% of people with obstructive sleep apnea also have insomnia. Most are only ever assessed for one of them.
Why they look like opposites
Sleep apnea is a breathing problem. The airway at the back of the throat collapses repeatedly, oxygen falls, and you surface briefly to reopen it — dozens or hundreds of times a night, almost none of which you remember. The classic presentation is someone who sleeps plenty and is exhausted anyway.
Insomnia is a sleep-initiation and maintenance problem. You cannot fall asleep, or you wake at 3am and cannot get back. The classic presentation is someone lying awake, frustrated, watching the clock.
One is "sleeps too much and gets nothing from it." The other is "cannot get to sleep at all." So clinicians, and patients, tend to pick a lane.
How each one hides the other
Here is the mechanism that makes this so easy to miss.
Insomnia masks apnea. The loudest apnea symptom is snoring, and snoring is what gets people referred. Someone who takes two hours to fall asleep describes their problem as insomnia, gets treated for insomnia, and nobody asks the bed partner about snoring. If they sleep alone, nobody asks at all.
Apnea masks insomnia. Someone diagnosed with apnea and started on CPAP who still sleeps badly gets recorded as poorly adherent, or as needing a pressure adjustment. The possibility that they have a second, independent condition often does not come up.
And apnea can cause insomnia. Repeated arousals through the night fragment sleep and can establish exactly the pattern — waking at 3am, unable to settle — that looks like textbook sleep-maintenance insomnia.
Why it matters more than either alone
This is the part that moved us to write the article.
Health Newspapers covered a six-year cohort of 2,401 patients published in the Journal of Clinical Sleep Medicine in April 2026, and the numbers are not subtle. Moderate-to-severe sleep apnea alone carried a hazard ratio for all-cause mortality of 2.65 (95% CI 1.12–6.30). The combination with insomnia carried a hazard ratio of 3.02 (95% CI 1.30–7.04). (Their write-up of the study and its limitations.)
In that cohort, 36.2% had moderate-to-severe apnea, 49.5% had insomnia, and 16.9% had both.
Worth reading those confidence intervals honestly — they are wide, which is what you expect from a cohort of this size, and this is an observational association rather than a demonstration of cause. But the direction is consistent with a broader literature showing COMISA carries higher cardiovascular risk and worse daytime functioning than either condition on its own.
The genuinely encouraging part
The treatment picture is better than the risk picture, which is not the usual pattern.
A small trial in Chest found that patients with both conditions responded to CPAP better than patients with apnea alone, at least on blood pressure. Over four weeks of auto-CPAP, the COMISA group dropped 6.0 mmHg systolic on average against 0.3 mmHg in the apnea-only group. (The reporting, including the caveats.)
Keep that in proportion: 71 patients in total, only 22 of them in the COMISA group, and the secondary outcomes lost statistical significance once corrected for multiple comparisons. It is a signal worth knowing about, not a settled finding.
The wider clinical picture is that COMISA responds to treating both — typically CBT-I for the insomnia alongside CPAP for the apnea — and that treating the insomnia first often improves CPAP tolerance, which is the single biggest determinant of whether apnea treatment works at all.
What this means if you are troubleshooting your own sleep
Most of this site is about the controllable inputs — light timing, caffeine, alcohol, temperature, breathing. Those are the right place to start and they resolve a great deal.
COMISA is the explanation for a specific pattern: you have worked the list properly and it has not helped.
Worth getting assessed for both if you recognise several of these:
- You snore, and you lie awake (how to find out if you snore when you sleep alone)
- You wake at 3am regularly and cannot settle
- You are exhausted regardless of hours (the full checklist)
- Witnessed breathing pauses, gasping awake, or morning headaches (the six causes)
- You were treated for insomnia and it did not work
- You are on CPAP and still sleep badly
- Sleeping tablets have not fixed it — and note that sedatives relax the upper airway and lengthen obstructive events, so they can make undiagnosed apnea worse (why you should not tape on them either)
Ask for a sleep study, and mention the insomnia explicitly rather than letting it be the headline that stops the conversation. (How to decide whether you need one.)
Where the products on this site do and do not fit
Directly: neither mouth tape nor nasal strips treats either condition. Apnea is a collapse of the throat, and insomnia is not a breathing problem at all.
If assessment rules both out and what remains is a mouth-breathing habit with a clear nose, the mechanical tools are reasonable — and nasal breathing genuinely does shift the autonomic balance toward the parasympathetic state that sleep onset depends on. (Titan's summary of that research, with the papers cited.)
But that is a comfort and recovery question. The one on this page is a clinical one, and it comes first.
The bottom line
Insomnia and sleep apnea coexist in 30–50% of apnea cases, each conceals the other, and the combination carries higher risk than either alone.
If you both snore and lie awake — or you were treated for one and nothing improved — ask to be assessed for both. The treatment picture for COMISA is genuinely good, and the main obstacle is that hardly anyone gets screened for the second condition.