ADHD, Sleep Apnoea and the Sleep Disorders Frequently Missed

Obstructive sleep apnoea (OSA) is significantly over-represented in adults with ADHD, somewhat over-represented in autistic adults, and routinely missed in both. Several other sleep disorders sit in a similar pattern: present at higher than general-population rates, with symptoms that overlap with the underlying neurodivergent picture, and rarely the first thing the clinician considers. This piece covers the main candidates, why they get missed, how to get assessed in the UK, and what the consequences of leaving them untreated look like.

Sleep apnoea: the most-missed sleep disorder in ADHD

Obstructive sleep apnoea is the most common sleep disorder you have probably not been assessed for. Repeated upper airway obstruction during sleep produces brief arousals, oxygen desaturation, fragmented sleep, and downstream cognitive and cardiovascular effects.

The general population prevalence is high (around 9 percent of women and 17 percent of men in middle age, by AASM criteria) and rises substantially with age and BMI. In adults with ADHD, the rate is materially higher than the general population. Sedky and colleagues' 2014 Sleep Medicine Reviews meta-analysis documented the strong link in paediatric populations ^[1]; the adult picture follows and is widely reported in clinical practice though less precisely quantified.

The mechanism is not fully understood but several plausible contributors stack up. Adults with ADHD are at higher risk of obesity (a major OSA risk factor). Adults with ADHD are more likely to use alcohol heavily (which worsens OSA). Adults with ADHD often have poor sleep posture and disrupted sleep schedules that compound any underlying breathing pattern. The combined effect: a meaningful proportion of adults with ADHD have undiagnosed OSA contributing to a sleep picture that is being attributed entirely to ADHD.

How sleep apnoea symptoms mimic ADHD

The clinical symptoms of moderate-to-severe OSA in adults include:

• Daytime sleepiness, including falling asleep in inappropriate situations
• Difficulty concentrating
• Memory problems
• Mood changes (low mood, irritability)
• Morning headaches
• Loud snoring with witnessed pauses in breathing
• Choking or gasping awakenings
• Frequent night-time waking, often unremembered

Look at that list and notice how much of it overlaps with ADHD presentation. The cognitive symptoms, the mood changes and the difficulty concentrating are present in both. A clinician taking a history from a 50-year-old man who has been on ADHD medication for years and is still having cognitive problems may not think to ask about snoring.

This matters clinically. Many adults with ADHD who have spent years on stimulant treatment without the expected response turn out to have moderate or severe OSA running underneath. Treating the OSA often produces substantial improvement in cognition, mood and ADHD symptom severity, sometimes more substantial than further adjustment of the ADHD medication. The Hvolby 2015 review covers the picture clearly ^[6]. See our ADHD and sleep: why switching off is so hard piece for the broader circadian and dopamine picture.

What this means for autistic adults

The autism-OSA literature is younger than the ADHD-OSA literature and less precisely quantified. Veatch and colleagues' 2017 work in Autism Research and the broader autism-sleep literature support a higher rate of sleep-disordered breathing in autistic adults than in the general population, though the effect size is smaller than for ADHD and the mechanism less clearly characterised ^[2].

For autistic adults specifically, the additional consideration is that sensory profile may make OSA assessment and treatment harder. A polysomnography study (sleep in a clinical setting with sensors) is sensory-hostile; a CPAP mask is a significant sensory challenge for many autistic patients. These are not reasons not to investigate or treat; they are reasons to have an autism-literate sleep clinician where possible, and to ask the clinical team to work with you on the sensory adjustments. See our pieces on autism and sleep: the biological overlap and autism and healthcare in the UK for the wider context.

Other sleep disorders worth knowing about

Beyond OSA, several other sleep disorders sit in the over-represented-and-often-missed pattern for adults with ADHD or autism:

• Restless legs syndrome (RLS) and periodic limb movement disorder (PLMD). Significantly over-represented in adults with ADHD. The discomfort is real, often not recognised as a separate clinical picture, and often treatable. Iron deficiency is a common contributor and is worth checking; some adults with ADHD respond to iron repletion alone.
• Narcolepsy spectrum disorders. Less common but worth knowing about. Excessive daytime sleepiness that does not respond to expected interventions, particularly with cataplexy (sudden muscle weakness triggered by emotion), warrants specialist sleep medicine assessment.
• Idiopathic hypersomnia. Chronic excessive sleepiness without other explanation. Sometimes confused with ADHD, sometimes co-occurring.
• Parasomnias (sleepwalking, night terrors, REM behaviour disorder). Can be present in any of the above groups; usually warrant assessment when frequent or severe.
• Insufficient sleep syndrome. Often dismissed as "you just need to go to bed earlier", but in adults with ADHD or autism the underlying reasons for the inadequate sleep matter and may need their own intervention.

How to get assessed in the UK

The general UK pathway:

Step 1: Screening. The STOP-BANG questionnaire is the standard screening tool for OSA risk and is freely available ^[5]. Eight yes-or-no questions covering snoring, tiredness, observed apnoea, blood pressure, BMI, age, neck circumference, gender. A score of 3 or more flags moderate risk; 5 or more flags high risk. Bringing a completed STOP-BANG to your GP is a useful starting point.

Step 2: GP referral. For suspected OSA, your GP can refer to NHS sleep medicine or a respiratory clinic. Some areas now offer direct home sleep study referral; in others a sleep clinic appointment comes first.

Step 3: Sleep study. Most adults are now assessed with a home sleep study (a small portable device worn overnight that measures breathing and oxygen). Polysomnography in a sleep clinic is reserved for more complex pictures.

Step 4: Treatment. For confirmed moderate-to-severe OSA, CPAP (continuous positive airway pressure) is the first-line treatment with the strongest evidence base ^[3]. For milder cases, mandibular advancement devices, positional therapy and weight management may be appropriate.

For non-OSA sleep disorders (RLS, narcolepsy, parasomnias), the route is GP referral to sleep medicine, neurology or specialist sleep psychology depending on the picture.

What this means in practice

• Obstructive sleep apnoea is materially over-represented in adults with ADHD and somewhat over-represented in autistic adults; it is the most-missed sleep disorder in this group.
• OSA symptoms (cognitive difficulty, daytime sleepiness, mood change) overlap with ADHD presentation; many adults on long-term ADHD treatment with incomplete response turn out to have undiagnosed OSA.
• Restless legs syndrome, periodic limb movements, narcolepsy spectrum and parasomnias are also over-represented; the threshold for specialist assessment should be low where significant sleep symptoms persist.
• The UK assessment route: STOP-BANG screening, GP referral, home sleep study for OSA, sleep medicine for the wider picture.
• For autistic adults, sensory considerations (polysomnography environment, CPAP mask tolerance) need explicit attention; an autism-literate sleep clinician is in a different category.

When to speak to a professional

Speak to your GP with a completed STOP-BANG questionnaire if you have any combination of loud snoring (your partner is the witness), daytime sleepiness, morning headaches, witnessed breathing pauses, or chronic cognitive symptoms that have not improved with ADHD treatment. For restless legs, severe daytime sleepiness, or other significant sleep symptoms, GP referral to sleep medicine is the route. NeuroFX is not a sleep medicine service; our adult ADHD assessment and adult autism assessment services can support the wider picture but the sleep-disorder assessment route is NHS sleep medicine or a specialist private sleep clinic.

Sources

1. Sedky K, Bennett DS, Carvalho KS. ADHD and sleep disordered breathing in pediatric populations: a meta-analysis. Sleep Medicine Reviews. 2014;18(4):349-356.
2. Veatch OJ, Sutcliffe JS, Warren ZE, Keenan BT, Potter MH, Malow BA. Shorter sleep duration is associated with social impairment and comorbidities in ASD. Autism Research. 2017;10(7):1221-1238.
3. Patil SP, Ayappa IA, Caples SM, Kimoff RJ, Patel SR, Harrod CG. Treatment of adult obstructive sleep apnea with positive airway pressure: an American Academy of Sleep Medicine clinical practice guideline. Journal of Clinical Sleep Medicine. 2019;15(2):335-343.
4. British Thoracic Society. Position statement on obstructive sleep apnoea/hypopnoea syndrome. https://www.brit-thoracic.org.uk/
5. Chung F, Yegneswaran B, Liao P, et al. STOP questionnaire: a tool to screen patients for obstructive sleep apnea. Anesthesiology. 2008;108(5):812-821.
6. Hvolby A. Associations of sleep disturbance with ADHD: implications for treatment. Attention Deficit and Hyperactivity Disorders. 2015;7(1):1-18.
7. NICE Clinical Knowledge Summaries. Obstructive sleep apnoea syndrome. https://cks.nice.org.uk/topics/obstructive-sleep-apnoea-syndrome/