Hypersomnolence is characterized by recurrent episodes of excessive daytime sleepiness or prolonged nighttime sleep. It has previously been referred to as “hypersomnia,” but this name does not capture both components of its definition.
Rather than feeling tired due to lack of or interrupted sleep at night, persons with hypersomnolence are compelled to nap repeatedly during the day, often at inappropriate times such as during work, during a meal, or in the middle of a conversation. These daytime naps usually provide no relief from symptoms.
Patients often have difficulty waking from a long sleep and may feel disoriented. Other symptoms include:
- increased irritation
- decreased energy
- slow thinking
- slow speech
- loss of appetite
- memory difficulty
Some patients lose the ability to function in family, social, occupational, or other settings.
Some may have a genetic predisposition to hypersomnolence; in others, there is no known cause.
Hypersomnolence typically affects adolescents and young adults.
Specific Diagnostic Criteria for Hypersomnolence
The predominant feature is excessive sleepiness for at least 1 month (in acute conditions) or at least 3 months (in persistent conditions) as evidenced by either prolonged sleep episodes or daytime sleep episodes that occur at least 3 times per week.
- The excessive sleepiness causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
- The excessive sleepiness is not better accounted for by insomnia and does not occur exclusively during the course of another sleep disorder (e.g., narcolepsy, breathing-related sleep disorder, circadian rhythm sleep disorder, or a parasomnia)
- It cannot be accounted for by an inadequate amount of sleep.
- 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.
Hypersomnolence can co-occur with another mental or medical disorders, though this condition cannot adequately explain the predominant complaint of hypersomnolence. In other words, the hypersomnolence is significant enough to warrant its own clinical attention and treatment.
It can result from a physical problem, such as a tumor, head trauma, or injury to the central nervous system. Medical conditions including multiple sclerosis, depression, encephalitis, epilepsy, or obesity may also contribute to the disorder.
This entry has been updated according to DSM-5 criteria; diagnostic code 307.44.