When You Have Insomnia and Sleep Apnea Together
The two most common sleep disorders overlap far more than either is diagnosed alongside the other, and their symptoms point in opposite directions. Treating one first is why treatment so often stalls.
If you have been told you have sleep apnea, given a CPAP machine, and found that your real problem is that you cannot fall asleep at all — this page is about you, and there is a name for it.
COMISA — comorbid insomnia and sleep apnea — is the overlap of the two most common sleep disorders. It is highly prevalent, and it is treated as though it were rare.
Why it gets missed
The clearest account of the problem comes from a 2025 review, and the reason it names is almost elegant (Meira e Cruz and Sweetman, Seminars in Respiratory and Critical Care Medicine, 2025).
COMISA has historically been under-recognised, partially because the symptoms of the two conditions conflict: insomnia presents with hyperarousal and sleeplessness, while sleep apnea presents with sleep fragmentation and excessive daytime sleepiness [Meira e Cruz 2025].
Read what that does diagnostically. Someone with both walks in reporting difficulty falling asleep and daytime exhaustion. To an insomnia lens, the sleepiness is a consequence of not sleeping. To a sleep apnea lens, the trouble settling is stress or poor sleep hygiene. Each condition offers a ready explanation for the other's symptoms, so whichever specialist sees you first tends to find their own diagnosis sufficient.
The review also notes COMISA is associated with greater impairment in sleep, daytime functioning, and physical and mental health than insomnia or sleep apnea alone [Meira e Cruz 2025]. Having both is worse than the sum of having each.
And importantly: COMISA may not be merely the coexistence of two conditions but may involve unique pathophysiological interactions [Meira e Cruz 2025] — meaning it may behave as its own entity rather than two problems sharing a patient.
Tier 2 for the framing and the interaction hypothesis; the prevalence and the impairment are well described. How we grade evidence.
Why it breaks CPAP
This is the practical heart of it, and it explains a specific, common and demoralising failure.
CPAP asks you to fall asleep wearing a mask with pressurised air. That is a modest ask for someone who falls asleep easily. For someone with insomnia — whose central difficulty is a hyperaroused nervous system that will not let go — it adds a novel physical stimulus at exactly the wrong moment.
The result is a pattern many people recognise: the machine is tolerable once asleep, and the problem is getting there. Hours awake wearing it, then removing it in frustration.
That gets recorded as poor adherence, and recorded as poor adherence it looks like a motivation problem. It is not. It is an untreated second condition obstructing treatment of the first.
There is a plausible physiological dimension too. A low arousal threshold — waking easily from minor respiratory disturbance — is one of the four traits that shape how apnea behaves, and it overlaps conceptually with insomnia's hyperarousal. Why treatments work for some people and not others.
The order that matters
The clinical direction of travel is toward treating the insomnia component first or alongside the apnea, rather than after it.
The rationale is straightforward: cognitive behavioural therapy for insomnia is the first-line treatment for chronic insomnia, and someone who can fall asleep is someone who can use a CPAP machine. Treating apnea first in a patient who cannot initiate sleep means asking them to adhere to a therapy their other condition prevents.
This is a shift from the older assumption that fixing the breathing would fix the sleep. For many patients it does not, because the insomnia is not downstream of the apnea.
Two practical implications:
Ask specifically about CBT-I. It is the evidence-based insomnia treatment, it is available in digital as well as in-person formats, and it is not the same thing as generic sleep hygiene advice.
Do not accept sedatives as the answer to CPAP intolerance. Sedative-hypnotics relax the upper airway dilator muscles and can worsen obstructive events. Using one to tolerate treatment for a condition it aggravates is the wrong trade, and it is worth raising explicitly if one is offered. Sedatives that make snoring worse.
What to say to get it recognised
The symptom pair is what identifies you, so report both halves in the same breath rather than answering whichever question is asked:
- "I cannot fall asleep" or "I wake at 3am and cannot get back to sleep" — the insomnia half
- "And I am exhausted all day" — the apnea half
- "And I snore" or "my partner has seen me stop breathing" — what makes it apnea rather than insomnia alone
If you are already on CPAP: "the mask is fine once I am asleep, I just cannot get to sleep in it" is the sentence that distinguishes an insomnia problem from a mask-tolerance problem. They have completely different solutions, and they get confused constantly.
If your difficulty is genuinely the equipment — fit, pressure, dryness, leak — that is the other diagnosis and it is very fixable. Getting used to CPAP · Mouth leak.
Why this matters beyond comfort
Someone whose apnea goes untreated because an unrecognised insomnia blocked the treatment carries the full cardiovascular and cognitive risk of untreated apnea — and it will be recorded as their own non-adherence.
That is the cost of missing this: not just worse sleep, but a treatable condition left untreated for a reason nobody named. What untreated apnea does · What happens after a diagnosis.
The line
No consumer product treats either condition. Mouth tape, nasal strips and pillows do not treat obstructive sleep apnea, and nothing sold for sleep treats chronic insomnia — the treatment for that is a structured behavioural therapy. Both halves of COMISA need real treatment. Snoring versus sleep apnea · Do sleep supplements help.