Circadian Rhythm Sleep-Wake Disorders


Circadian rhythm is the name given to the body’s internal clock that regulates sleep and wake cycles, hormones, hunger, digestion, and body temperature. Daylight and darkness trigger this process in the suprachiasmic nucleus, which is a protein cluster located in the hypothalamus (Pacheco, n.d.). This internal clock of sorts resets itself every 24-hours and is how our bodies know it is time to sleep and time to be awake. There are different types of disorders that can occur, altering this rhythm and causing sleep problems.

The delayed sleep phase type occurs when the cycle runs slower than 24-hours, causing a delay in the sleep cycle. People with this type tend to stay up late and sleep in and find themselves more alert in the evenings rather than in the mornings (Sadock et al., 2015).

The advanced sleep phase type is the opposite and occurs when the cycle runs faster than 24-hours. People with this type often get up very early in the morning and go to sleep early in the evening and are more alert in the early morning time (Sadock et al., 2015).

The irregular sleep-wake type is when the circadian rhythm is barely functioning or not functioning at all. People with this type tend to sleep several hours at a time all throughout the 24-hour period, instead of getting all of their sleep during the nighttime hours. This is the type that usually causes insomnia and excessive tiredness during the daytime.

Finally, there is the non-24-hour sleep-wake type, or free running type. This type is most common with blindness or TBI’s, when the perception of darkness and light are altered (Sadock et al., 2015). This causes the cycle to be either more or less than 24-hours and the main symptom is severe difficulty in falling asleep.

The diagnostic criteria for circadian rhythm disorders according the DSM-5 are as follows. There must be a “persistent or recurrent pattern of sleep disruption that is primarily due to an alteration of the circadian system or to a misalignment between the endogenous circadian rhythm and the sleep-wake schedule required by an individual’s physical environment or social or professional schedule” (American Psychiatric Association [APA], 2013, Circadian Rhythm Sleep-Wake Disorders section). This disruption in sleep must result in “excessive sleepiness, insomnia, or both”, and it must also cause significant impairment of one’s ability to function socially, academically, or professionally (APA, 2013, Circadian Rhythm Sleep-Wake Disorders section).

The best pharmacological treatment for a circadian rhythm sleep disorder is melatonin. Melatonin is produced naturally by the body and the levels or highest in the evening. This aids the person to slow down and tells their body it’s almost time to go to sleep. Melatonin supplements can take to aid in this process. A good sleep hygiene schedule is also important to maintain, in order to retrain the brains circadian rhythm. This means going to bed at the same time every night and waking up at the same time every morning. It can also mean developing a routine before bed each night, so your body starts to correlate the routine with bedtime. It is also important to sleep in complete darkness as any kind of light disrupts the rhythm and reduces melatonin levels. Exposing oneself to bright light in the morning hours can also help to restart the clock.

If none of these methods help promote a healthy sleep schedule, then the patient may need to be referred to a specialist. Some medical causes to consider are sleep apnea, brain tumors, Parkinson’s disease, anxiety, depression, brain injuries, and Alzheimer’s disease. It is important to rule these medical causes out if melatonin and sleep hygiene do not help.


American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.).

Pacheco, D. (n.d.). Circadian rhythm sleep disorders. Sleep Foundation.

Ronningstam, E. (2014). Gabbard’s treatments of psychiatric disorders. American Psychiatric Publishing.

Sadock, B. J., Sadock, V. A., & Ruiz, P. (2015). Kaplan & Sadock’s synopsis of psychiatry: Behavioral sciences/clinical psychiatry (11th ed.). Wolters Kluwer.