Non-24-hour sleep-wake disorder (N24) is a circadian rhythm sleep disorder in which an individual's biological clock fails to synchronize to a 24-hour day. Instead of sleeping at roughly the same time every day, someone with N24 will typically find their sleep time gradually delaying by minutes to hours every day.

Tasimelteon is used to treat non-24-hour sleep-wake disorder (non-24; a condition that occurs mainly in people who are blind in which the body's natural clock is out of sync with the normal day-night cycle and causes a disrupted sleep schedule) in adults.

Hetlioz (tasimelteon) is also used to treat sleep disturbances in patients with Smith-Magenis Syndrome (SMS). It's the first and currently only FDA-approved treatment for people with non-24 and SMS. Since it's only available as a brand name, it can be expensive.

Treatment for non-24-hour sleep-wake disorder (N24SWD) aims to establish a 24-hour sleep-wake cycle, or “entrain (synchronize) the circadian rhythm.” This process commonly involves using melatonin, bright light therapy, or other methods that are known to influence the circadian rhythm.

Non-24 is a circadian rhythm disorder and occurs because our internal clock is not synched with light and dark cycles of the day and night. Most individuals with this disorder are totally blind. That's because your internal clock gets its cue from seeing light. But sometimes people who have normal vision also get it.

People who are blind also use screen readers on touch screen phones and tablets. This kind of software reads aloud all the text on the screen, including navigation buttons. Android devices use an app called Talkback. Apple iOS devices use built-in software known as VoiceOver, which uses text-to-speech output.

Blind individuals with no light perception develop circadian desynchrony. This leads to non-24-hour sleep-wake rhythm disorder, which is associated with sleep-wake disorders, as well as mood disorders and loss of appetite and gastrointestinal disturbances due to disrupted circadian hormone regulation.

Welcome to HETLIOZ® (tasimelteon) The first and only FDA-approved treatment for Non-24-Hour Sleep-Wake Disorder (Non-24).

HETLIOZ®(HeT-lee-ōz) [tasimelteon] capsules are indicated for the treatment of: Non-24-Hour Sleep-Wake Disorder (Non-24) in adults. Nighttime sleep disturbances in Smith-Magenis Syndrome (SMS) patients 16 years of age and older.

There's no cure, but treatments, including hormones, medicine, and light therapy, can help get you closer to a normal sleeping pattern.

People with DSPS cannot fall asleep until very late and therefore need to sleep late in the day, or they become chronically sleep deprived. They can manage to stay on a 24-hour schedule, just not sleeping at the usual time of night. People with Non-24 have more than 24 hours in their day.

A person is considered legally blind if he/she has central visual acuity of 20/200 or worse in the better-seeing eye with best correction (using glasses or contact lenses) at a distance, or if he/she has visual field restriction where the widest diameter is 20 degrees or less in the better-seeing eye.