Written by:
August 24, 2018

Autism & sleep problems: Causes

Last updated on February 24, 2021

This is part 2 of a 4-part series on autism and sleep problems

Autism & sleep problems: Prevalence
Autism & sleep problems: Causes
Autism & sleep problems: Effects
Autism & sleep problems: Solutions


Causes of sleep problems

A study from 2017 that looked at sleep problems in autistic children and children with ADHD indicated that the causes of sleep problems are different for each group:[1]Sleep, chronotype, and sleep hygiene in children with attention-deficit/hyperactivity disorder, autism spectrum disorder, and controls


Sleep disorders

A study from 2015 indicated that 59% of autistic people had symptoms indicative of at least one sleep disorder, with sleep-breathing disorders (SBD) as the most commonly reported (38%), compared to 1.8% in controls.[4]Influence of sleep disorders on the behavior of individuals with autism spectrum disorder


Melatonin

Another issue and underlying cause of sleep problems in autism is low melatonin levels. Melatonin is a hormone that regulates sleep and wakefulness.

Studies show that autistic people have lower nighttime melatonin or melatonin metabolite concentrations compared to neurotypicals,[5]Melatonin in autism spectrum disorders: a systematic review and meta‐analysis and show lower activity of the ASMT gene, as well as some splicing mutations in the ASMT gene in some autistic individuals, which also results in lower melatonin levels.[6]Abnormal melatonin synthesis in autism spectrum disorders

Have a look at the table below for an overview of melatonin issues reported in autism.[7]Melatonin in autism spectrum disorders: a systematic review and meta‐analysis

Embrace Autism | Autism & sleep problems: Causes | table MelatoninValuesASD
Table attribution: Daniel A. Rossignol & Richard E. Frye

Melatonin effects

In the forest plots below, you can see the effect of melatonin on several sleep parameters—sleep duration, sleep latency, and night-time awakenings—in autistic people compared with baseline and placebo.[8]Melatonin in autism spectrum disorders: a systematic review and meta‐analysis

Sleep duration
Embrace Autism | Autism & sleep problems: Causes | diagram MelatoninSleepParameters Duration
Melatonin demonstrates a significant effect on sleep duration compared with both baseline and placebo using both effect size calculations. (Image attribution: Daniel A. Rossignol & Richard E. Frye)
Sleep onset latency
Embrace Autism | Autism & sleep problems: Causes | diagram MelatoninSleepParameters Latency
Melatonin demonstrates a significant effect on sleep onset latency compared with both baseline and placebo using both effect size calculations. (Image attribution: Daniel A. Rossignol & Richard E. Frye)
Night-time awakenings
Embrace Autism | Autism & sleep problems: Causes | diagram MelatoninSleepParameters Awakenings
Melatonin demonstrates no significant effect on night-time awakenings as compared with both baseline and placebo using both effect size calculations. CI, confidence interval. (Image attribution: Daniel A. Rossignol & Richard E. Frye)

So as you can see, melatonin has a significant effect on sleep duration and sleep onset latency—but not night-time awakenings—in autistic people.


Effect of the Moon

Light, in general, suppresses melatonin levels, and in particular blue monochromatic light at a wavelength of 446–477 nm.[9]Blue light from light-emitting diodes elicits a dose-dependent suppression of melatonin in humans

The Moon—being a light source—also affects melatonin levels, and in fact, the lunar cycle modulates human sleep and melatonin rhythms. The diagram below shows that the time taken to fall asleep is longer during full moon.[10]Evidence that the Lunar Cycle Influences Human Sleep

Embrace Autism | Autism & sleep problems: Causes | diagram SleepLatencyLunarCycle
Time to fall asleep and lunar phase; color-coded symbols show the different gender and age groups: dark blue for young men, tan for young women, light blue for older men, and white for older women. (Image attribution: Christian Cajochen et al. – redesigned by Embrace ASD)

Since autistic people already have issues with sleep problems and low melatonin levels, the lunar cycle—and in particular the full moon—can be a major contributor. Read more:

The effect of Moon phases

Embrace Autism | Autism & sleep problems: Causes | icon Sleep1

Next: Autism & sleep problems: Effects
This article
was written by:
martin-silvertant

Co-founder of Embrace Autism, I’m living up to my surname as a silver award-winning graphic designer. Besides running Embrace Autism and researching autism, I love typography and practice type design. I also fight dodecahedragons during sleep onset.

I discovered I’m autistic when I was 19, and was diagnosed at 25.

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