November 2020 | Reviewed by: Shelley Hershner, MD and John Saito, MD
What is irregular sleep-wake rhythm disorder?
Irregular sleep-wake rhythm disorder (ISWRD) is one of several circadian rhythm disorders.
Normally, people are awake and asleep in rhythm with their biological clock. This is known as the circadian rhythm. It typically is a cycle that spans 24 hours and synchronizes to a 24-hour day.
If you have ISWRD, then you show no clear circadian rhythm. You struggle with wakefulness during conventional sleeping hours and sleepiness during the daytime. Your sleep and wake times show no clear pattern.
People with ISWRD may sleep off and on in a series of naps over a 24-hour period. This is similar to infants who may sleep for a few hours and then be awake for a few hours. By definition, to have ISWRD means you must have at least 3 sleep periods within a 24-hour period.
During the day, it may seem like you are sleepy because you nap so much. During the night, it may seem like you have insomnia because you are awake for long periods of time. There is not one main sleep time that occurs at any time of the day or at night. If you add up all of your sleep times, your total sleep time may not be normal for your age.