A persistent or recurrent pattern of sleep disruption leading to excessive sleepiness or insomnia that is due to a mismatch between the sleep-wake schedule required by a person’s environment and his or her circadian sleep-wake pattern. In other words, a person’s natural biological clock for sleep is at odds with times required for them to go to sleep and wake up. For example, an individual may have trouble falling asleep early enough to feel rested for work the next day, ultimately leading to difficulty following their required schedule.

Others may exhibit a variable sleep pattern (e.g., take multiple naps instead of sleeping an extended block of time) throughout the regular 24 hr period leading to similar sleepiness or trouble concentrating during the socially conventional awake period. Insomnia and excessive sleepiness during work hours can also be induced in shift workers due to their unconventional schedule.

The sleep disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.

The disturbance does not occur exclusively during the course of another sleep disorder or other mental disorder.

The disturbance is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition.

This criteria has been updated for DSM-5. Diagnostic code: 307.45.