Thanks to the biological clock in humans, physical and mental events are repeated in a 24-hour cycle. In patients with non-24-hour sleep-wake disorder (N24), this biological clock is disrupted by an unknown mechanism, and the person cannot repeat the sleep-wake process in a 24-hour cycle. N24 patients may fall asleep and wake up a few minutes to hours earlier or later than the previous day. If left untreated, it can lead to significant physical, mental, or social problems. Trying to insist on a regular 24-hour sleep pattern without treatment may worsen the situation.