A good night’s sleep can be hard to come by if you are blind and have a common disorder known as Non-24. At a recent information session held at Perkins School for the Blind, Vanda Pharmaceuticals’ medical science liaison Aaron Sheppard explained the science behind Non-24, which affects a majority of the world’s blind population. Here are eight things you might not know about this condition:
- Non-24 is short for Non-24 Hour Sleep-Wake Disorder, but the condition goes by many other names, including Free Running Disorder, Hypernychthemeral Disorder and Circadian Rhythm Disorder.
- Non-24 is caused by the body’s inability to align its day/night circadian rhythms with the surrounding environment. For people who are sighted, light acts as the body’s cue to align its internal clock with a 24-hour day. For people who are blind and lack light perception, the body acts according to its natural circadian rhythm, which may be longer or shorter than 24 hours.
- Individuals who are sighted can also suffer from Non-24, although it is rare. In some cases, the cause is unknown. In other cases, sighted people can develop Non-24 after suffering brain injuries or head trauma.
- Symptoms of Non-24 include insomnia at night coupled with lower alertness during the day. The sleep deprivation can make it extremely difficult for people who suffer from Non-24 to thrive in the workplace or engage in social activities, and can lead to cognitive dysfunction and depression.
- The first case of Non-24 was recorded in 1970 by three scientists from the University of Manchester (U.K.), who studied a sighted man unable to live according to a 24-hour day. They later published their findings in a paper entitled “A man with too long a day.”
- It is estimated that up to 70 percent of people who are totally blind suffer from Non-24. The disorder can affect anyone at any age, from children to adults.
- Vanda Pharmaceuticals received FDA approval in 2014 to produce the first-ever treatment for Non-24 for people 18 and older. The drug, known as Hetlioz, acts on receptors in the brain for melatonin, a hormone that helps to control the sleep-wake cycle.
- Despite its prevalence among the blind population, many individuals don’t know they have Non-24. This can be attributed to the cyclical nature of the disorder, which can cause severe insomnia for a week, followed by three weeks of restful nights. Doctors also commonly mistake Non-24 for depression or other sleep disorders.
For more information about Non-24, visit the Non-24-Hour Disorder Resource or the National Sleep Foundation.