By Jennifer Copley (Last Updated 30 March 2012)
Autistic spectrum disorders are often accompanied by a number of additional conditions, including difficulty sleeping, which afflicts up to 70% of autistic children (Andrew Zimmerman, MD, cited in Laino, 2009). Some studies have shown that children with autism tend to be deficient in melatonin, which is known as the “sleep hormone” because of the key role it plays in both circadian rhythms and seasonal rhythms (Laino, 2009; Melke et al., 2007; Rossignol, 2011).
How Melatonin Works
The pineal gland in the brain secretes melatonin to regulate circadian rhythms (sleep cycles). This gland produces more melatonin in darkness, and less in light, so bright lights at night or insufficient light during the day can have a negative impact on melatonin cycles. This is why working graveyard shifts, jet lag, and poor vision can all adversely affect melatonin. Melatonin also has antioxidant effects, so it may boost immune response. Studies have shown that melatonin is more effective in helping people fall asleep than a placebo (University of Maryland Medical Center, 2011).
A number of researchers have found that melatonin may improve the sleep of those with autistic spectrum disorders by enabling them to fall asleep more quickly and easily and stay asleep for longer (Laino, 2009). Overall, the evidence for this intervention is quite strong.
Studies of Melatonin for Autistic Spectrum Disorders
In 18 studies of melatonin’s efficacy for improving sleep in autistic children, subjects gained an average of 73 minutes of additional sleep and were able to get to sleep 66 minutes earlier on average (Rossignol, 2011). In some study subjects, sleep problems have been eliminated completely (Solis, n.d.). One study also found a reduction in compulsive, ritualistic behaviours with melatonin supplementation (Laino, 2009).
A study conducted by Andersen et al. (2008) found that 60% of autistic study subjects receiving melatonin reported improved sleep while just 13% continued to suffer major sleep problems. Only one child in the study suffered a worsening of symptoms and one had an undetermined response. Just three children suffered side effects (morning sleepiness and bedwetting).
Autism Research Institute parent ratings of the use of melatonin for treating autistic symptoms suggest that melatonin is effective for many children with autistic spectrum disorders. Parents noted improvements in 65% of cases, no change in 27%, and a worsening of symptoms in only 8%. Ratings for Asperger’s syndrome were even better, with improvements observed in 75% of cases, no change in 20%, and a worsening of symptoms in just 6% (percentages add up to more than 100% because they are rounded up to the nearest whole number).
Melatonin Side Effects and Safety
Although most children in the studies tolerated melatonin well, possible problems associated with its use include the following:
- Daytime drowsiness
- Stomach cramps
- Anxiety and irritability (with high doses)
However, recent studies have found side effects to be minimal and largely confined to bedwetting and daytime drowsiness (Laino, 2009; Rossignol, 2011).
Unlike most other supplements that must be taken indefinitely to maintain their effects, there is some evidence that melatonin’s sleep benefits become permanent after 6-12 months, at which time the supplement can be discontinued (Laino, 2009).
According to the Mayo Clinic (2011): “Based on available studies and clinical use, melatonin is generally regarded as safe in recommended doses (5 milligrams daily) for up to two years. Available trials report that overall adverse effects are not significantly more common with melatonin than placebo.”
The long-term effects of taking melatonin are not known at this time, and more research is required to determine whether or not there is any risk associated with long-term use. However, sleeplessness can also have adverse impacts on health, so some parents may consider this risk worth taking.
If choosing to supplement, Dr. Brent A. Bauer (2009) of the Mayo Clinic recommends choosing synthetic melatonin supplements rather than those made from animal sources, as the latter may be contaminated or contain viruses.
Melatonin may interact with some medications or have adverse health effects for people suffering from certain conditions. Always consult a qualified medical practitioner before taking supplements or giving them to your child to ensure safe and effective dosing.
Other Autism Supplements
For more on the effectiveness of other supplements for treating autistic spectrum disorders, see the main Autism Supplements page. For a full list of articles on autism and Asperger’s syndrome, visit the main Autistic Spectrum Disorders page.
This article is not intended as a substitute for medical consultation or care. Health concerns should be referred to a doctor.
- Andersen, I.M.; Kaczmarska, J.; McGrew, S.G.; & Malow, B.A. (2008). “Melatonin for Insomnia in Children with Autistic Spectrum Disorders.” Journal of Children Neurology, 23(5), pp. 482-485.
- Bauer, B.A., MD. “Melatonin Side Effects: What Are the Risks? Is Melatonin a Helpful Sleep Aid — And What Should I Know About Melatonin Side Effects?” The Mayo Clinic, MayoClinic.com.
- Laino, C. (12 October 2009). “Melatonin Helps Autistic Kids Sleep.” WebMD.com.
- Melke, J.; Goubran Botros, H.; Chaste, P.; Betancur, C.; Nygren, G.; Anckarsäter, H.; Rastam, M.; Ståhlberg, O.; Gillberg, I.C.; Delorme, R.; Chabane, N.; Mouren-Simeoni, M.C.; Fauchereau, F.; Durand, C.M.; Chevalier, F.; Drouot, X.; Collet, C.; Launay, J.M.; Leboyer, M.; Gillberg, C.; Bourgeron, T.; & the PARIS Study. (2008). “Abnormal Melatonin Synthesis in Autism Spectrum Disorders.” Molecular Psychiatry, 13(1), pp. 90-98.
- Research Autism. (14 February 2012). “Melatonin and Autism.” ResearchAutism.net.
- Rossignol, D., Dr. (26 April 2011). “Treatment of Melatonin Dysfunction in Children with Autism Shows Improvement in Sleep and Daytime Behaviors.” PRNewsWire.com.
- Solis, M., PhD. (n.d.). “Melatonin Shows Promise for Improving Sleep Problems in Children with Autism.” AutismSpeaks.org.
The Mayo Clinic. (1 October 2011). “Melatonin (N-Acetyl-5-Methoxytryptamine).” MayoClinic.com.
- University of Maryland Medical Center. (20 January 2012). “Melatonin.” UMM.edu.