<unk>  <unk> -24 or N24SWD) is one of several chronic circadian rhythm sleep disorders (CRSDs). It is defined as a "chronic steady pattern comprising ... daily delays in sleep onset and<unk>  times in an individual living in a society". Symptoms result when the<unk> -entrained (free-running) endogenous circadian rhythm drifts out of alignment with the light–dark cycle in nature. Although this sleep disorder is more common in blind people, affecting up to 70% of the totally blind, it can also affect sighted people.<unk> -24 may also be comorbid with bipolar disorder, depression, and traumatic brain injury. The American Academy of Sleep Medicine (AASM) has provided CRSD guidelines since 2007 with the latest update released in 2015.
Non-24-hour sleep–wake disorder
Circadian rhythm sleep disorder
Delayed sleep phase disorder
Irregular sleep–wake rhythm
Advanced sleep phase disorder
Shift work sleep disorder
Excessive daytime sleepiness
Sleep state misperception