Autism and Insomnia in Adults: Why Sleep Is So Hard

Read time: 9 minutes

What you’ll learn:

• Why insomnia affects an estimated 60% of autistic adults, far above general population rates
• The three layers behind it: a neurobiological floor, a circadian system that’s harder to entrain, and a maintaining loop that keeps insomnia going once it starts
• Why masking during the day may be feeding wakefulness at night
• Why sleep hygiene checklists tend to fail this population, and what CBT-I targets instead
• What the evidence says about CBT-I for autistic adults, and what adaptations look like in practice

Maya got her autism diagnosis at 41. Her insomnia had been there since she was a teenager.

For two decades, she’d worked through the standard advice: no screens before bed, a consistent wake time, magnesium, melatonin, blackout curtains, a white noise machine, two different sleep apps, and a course of CBT for generalized anxiety that helped her anxiety considerably and her sleep not at all. Every clinician along the way treated her sleep as a downstream symptom — of stress, of overwork, of being “a worrier.” None of them asked about light sensitivity, or what her evenings looked like after a full day of consciously managing eye contact and conversational timing, or whether her brain ever felt sleepy versus just exhausted.

The diagnosis didn’t fix her sleep. But it gave her, for the first time, a frame that matched her experience: that her nervous system runs differently, and that difference touches sleep in specific, identifiable ways.

This is a composite case, not a single client’s history, but it represents something real in our practice. We’re seeing more adults who were diagnosed with autism later in life, often after years of insomnia that no one connected to it. If that’s you, here’s what’s going on, and where the path forward looks different from one more sleep hygiene checklist.

Insomnia Is Far More Common in Autistic Adults

The general adult population has an insomnia disorder rate of roughly 10%. Among autistic adults, the figure climbs to about 60%, based on a 2020 meta-analysis comparing sleep disturbances across autism and ADHD populations. The rate in autistic children is even higher, with most studies putting it between 50% and 80%.

That’s not a small gap. It points to something structural rather than coincidental, and the research on autism and sleep over the past several years has started to map what that structure looks like.

Insomnia isn’t the only sleep disorder with elevated rates in autistic adults. ASD is considered a broad risk factor for disrupted sleep, and restless leg syndrome, circadian rhythm disorders, and obstructive sleep apnea all appear at higher rates in this population than in the general public. This matters clinically: each of those has a different mechanism, a different treatment, and would be missed entirely by CBT-I. If you’re an autistic adult with unresolved sleep problems, the first job is identifying what’s driving them, because the answer shapes everything that follows.

Three Layers Make Sleep Harder for Autistic Adults

It helps to think of this as three layers stacked on top of each other. The first lowers the threshold for insomnia. The second makes the body’s internal clock harder to keep on schedule. The third is what keeps insomnia going once it’s started, and it’s the layer CBT-I is built to address.

The neurobiological floor

Autistic brains show measurable differences in the systems that regulate sleep and wakefulness. Two are worth understanding.

GABA is the brain’s primary sleep-promoting neurotransmitter. It works by inhibiting the brain regions responsible for arousal, which is part of how the body transitions into sleep. Autistic individuals tend to have fewer GABA-A receptors, the receptor type GABA binds to in order to produce that calming effect. Fewer receptors means less inhibition of arousal circuits, which means it takes more to switch the brain into a sleep-ready state.

Melatonin tells the body when night has arrived. In autism, melatonin production and timing are often disrupted: levels can run lower at night, the daily peak can shift later than expected, and the signal can be less stable overall. This is part of why melatonin supplements are so often the first thing tried, and also why they so often disappoint. Melatonin influences sleep timing. It doesn’t address conditioned arousal, racing thoughts, or any of the behavioural patterns that keep insomnia entrenched.

A circadian system that’s harder to keep on schedule

Your internal clock doesn’t run on its own. It needs regular cues, called zeitgebers, to stay synchronized with a 24-hour day. Light is the strongest one. Social rhythms, like regular mealtimes and routine social contact, are another.

Sensory sensitivity to light can mean autistic individuals avoid bright environments, particularly outdoor daylight, more than neurotypical people do. Less light exposure means a weaker signal reaching the part of the brain that sets the body’s clock. Reduced reliance on or access to predictable social rhythms removes a second source of timing input. The result, for some autistic adults, is a circadian system that drifts rather than holds steady.

This matters clinically. A pattern of falling asleep very late and waking very late isn’t always insomnia. Sometimes it’s a circadian rhythm that’s shifted later than the schedule a person is trying to keep, a condition called delayed sleep-wake phase disorder. The treatment for that looks different from the treatment for insomnia maintained by hyperarousal. Getting this distinction right at assessment matters, because the wrong target wastes months.

The loop that keeps insomnia going

This is where things connect to the general model of chronic insomnia, and where CBT-I does its work.

Research specifically testing the hyperarousal hypothesis in autistic adults found exactly what the standard insomnia model predicts: elevated cognitive arousal (racing thoughts, rumination, intolerance of uncertainty) and elevated somatic arousal (physical tension, an activated nervous system at bedtime) both predict worse insomnia severity. Once insomnia has been running for a while, the body and brain learn to associate the bed with being awake and frustrated rather than with sleep. The behaviours people use to cope, like extending time in bed to chase more sleep, napping to recover, or watching the clock, end up reinforcing the very pattern they’re meant to fix.

None of this is unique to autism. It’s the same maintaining cycle behind chronic insomnia in anyone. What’s different is the starting conditions: a lower neurobiological threshold for arousal, a circadian system with weaker anchoring, and often, an additional daytime load that doesn’t show up in the standard insomnia model at all.

Masking May Be Feeding Nighttime Arousal

A 2024 qualitative study from the University of Edinburgh interviewed autistic adults about their experience of insomnia, and one theme stood out: masking, the conscious effort to suppress autistic traits and perform neurotypical social behaviour throughout the day, appeared to carry a physiological cost that didn’t resolve by bedtime.

Participants described an inability to “switch off.” The sustained effort of monitoring eye contact, modulating tone, managing sensory input in shared spaces, and editing spontaneous responses all day doesn’t simply end when the day does. The arousal that effort generates can still be present hours later, in bed, with nothing left to mask and nowhere for that energy to go.

This is a distinctly autistic contribution to the same hyperarousal mechanism that drives insomnia generally. It’s worth naming because almost no consumer-facing content connects the dots between daytime masking and nighttime wakefulness, and because it reframes the problem usefully: the issue isn’t only what happens at 11 p.m. It’s also what happened all day before that.

Why Sleep Hygiene Advice Tends to Fall Short

Sleep hygiene checklists target the sensory layer: dim the lights, control the temperature, remove screens, keep a consistent schedule. These are reasonable and often helpful as a baseline, particularly given how much sensory sensitivity factors into autistic sleep difficulty.

What they don’t touch is the loop. Hygiene advice doesn’t address conditioned arousal between bed and wakefulness. It doesn’t address the racing thoughts and intolerance of uncertainty that keep the nervous system activated at bedtime. It doesn’t account for masking load carrying into the night. And it can’t distinguish circadian drift from insomnia, which means it sometimes targets the wrong problem entirely.

This is the gap between a sleep environment optimization and a treatment for a maintaining cycle. Most autistic adults who’ve struggled with insomnia for years have already optimized their sleep environment. The problem usually isn’t the room. It’s the loop.

What the Evidence Says About CBT-I for Autistic Adults

A 2025 systematic review in the Journal of Sleep Research looked specifically at CBT-I in people with neurodevelopmental conditions, including autism. Across eight studies and nearly 600 participants, two randomized controlled trials and six before-after studies found short-term effectiveness for CBT-I in this population, with some studies also reporting improvement in condition-specific symptoms beyond sleep.

The honest caveat: this evidence base is still young. Findings weren’t consistent across every study, and improvements weren’t always sustained at follow-up. But the direction is clear, and it lines up with what the mechanism suggests it should. CBT-I targets the loop, hyperarousal, conditioned wakefulness, and unhelpful sleep-related thoughts and behaviours. Those mechanisms have been independently confirmed in autistic adults specifically, not just assumed to transfer from general population research.

A separate pilot study has tested an acceptance-based variant of CBT-I, built around the idea that less direct effort at controlling sleep, paired with the standard behavioural tools, may suit some autistic adults better than a heavily restructuring-focused cognitive approach. Early results were encouraging, though still preliminary.

What CBT-I Looks Like When It’s Adapted for an Autistic Adult

The core protocol, sleep restriction, stimulus control, and addressing unhelpful sleep-related thoughts, stays the same. What changes is delivery.

A circadian assessment usually comes first, to rule out or identify delayed sleep-wake phase disorder before treating for insomnia. Sensory adjustments to the sleep environment, weighted blankets, sound dampening, specific bedding textures, are addressed early rather than treated as an afterthought. Communication tends to be direct and concrete, with written materials alongside verbal explanation rather than relying on metaphor or ambiguity. Stimulus control, the rule that bed is for sleep only, sometimes needs nuance: if the bed is also a person’s most sensory-safe space, a clearly defined wind-down period in bed using a calm, non-stimulating activity may work better than a rigid bed-only rule. And given how much daytime load can carry into the night, a good clinician will ask about masking and burnout, not just bedtime routine.

This isn’t a different treatment. It’s the same treatment, delivered with attention to the parts of the picture that generic protocols miss.

A Note on Diagnosis Timing

If your insomnia predates your autism diagnosis by years or decades, that’s common, not unusual. Diagnostic delay in autistic adults averages close to a decade from first contact with mental health services, and it’s longer for women, who are more often misdiagnosed at first evaluation. A lot of people spend years being treated for anxiety or depression when the underlying picture includes a neurotype that was never assessed. Sleep is often one of the clearest places this shows up, because the mechanisms involved (sensory sensitivity, circadian timing, masking load) are autism-specific even when the surface complaint, “I can’t sleep,” sounds like anyone else’s insomnia.

TL;DR

Insomnia affects roughly 60% of autistic adults, well above the general population rate. Three layers explain it: a neurobiological floor that lowers the threshold for arousal (GABA receptor differences, melatonin dysregulation), a circadian system that’s harder to keep entrained (reduced light exposure, weaker social rhythms), and a maintaining loop of hyperarousal and conditioned wakefulness that’s identical in structure to standard chronic insomnia. Daytime masking appears to add to nighttime arousal in ways most sleep advice doesn’t account for. Sleep hygiene checklists address the sensory layer but leave the maintaining loop untouched, which is why they often fall short for autistic adults who’ve already tried everything. CBT-I targets that loop directly. Current evidence shows short-term effectiveness in autistic adults specifically, with adaptations around circadian assessment, sensory environment, communication style, and awareness of masking load, but without changing the core protocol.

Insomnia Doesn’t Have to Be Something You Manage Around

If you’re an autistic adult who’s tried the standard advice and your sleep hasn’t moved, the problem likely isn’t your effort. It’s that the standard advice was built for a different starting point. CBT-I is designed to work with the mechanisms driving your insomnia, adapted to fit how your nervous system works rather than asking you to override it.

Book a free 15-minute consultation to talk through what’s been keeping you up, and whether CBT-I is the right next step.

About the author

Graeme Thompson, MA, RCC, is a Registered Clinical Counsellor (#21951, BCACC) and the founder of BC CBT-I, a virtual practice providing Cognitive Behavioural Therapy for Insomnia to clients across British Columbia.

References

Baker, E. K., Richdale, A. L., Hazi, A., & Prendergast, L. A. (2019). Assessing a hyperarousal hypothesis of insomnia in adults with autism spectrum disorder. Autism Research, 12(6), 897–910. https://doi.org/10.1002/aur.2094

Cullen, K., et al. (2025). Effectiveness of cognitive behavioural therapy for insomnia (CBT-I) in individuals with neurodevelopmental conditions: A systematic review. Journal of Sleep Research. https://doi.org/10.1111/jsr.70058

Deserno, M. K., et al. (2019). Sleep determinants in individuals with autism spectrum disorder: A systematic review and meta-analysis. Sleep Medicine Reviews.

Gardani, M., et al. (2024). Experiences of and treatment preferences for insomnia in autistic adults: An interpretative phenomenological analysis. European Sleep Research Society.

Mazzone, L., et al. (2021). Insomnia severity in adults with autism spectrum disorder is associated with sensory hyper-reactivity and social skill impairment. Journal of Autism and Developmental Disorders.

Sannar, E. M., et al. (2025). Sleep and autism: Current research, clinical assessment, and treatment strategies. Current Psychiatry Reports.

Schwichtenberg, A. J., et al. (2020). Sleep in adults with autism spectrum disorder and attention deficit/hyperactivity disorder: A systematic review and meta-analysis. Sleep Medicine Reviews, 51.

Tonacci, A., et al. (2021). Gender differences in misdiagnosis and delayed diagnosis among adults with autism spectrum disorder with no language or intellectual disability. Brain Sciences.