Hypersomnia is the persistent excessive sleeping during daytime or prolonged nocturnal sleeping. The condition is also referred as essential hypersomnolence, non-REM narcolepsy or idiopathic CNS hypersomnia. This is not the same with fatigue felt due to night-time interrupted sleep or lack of sleep. Individuals with hypersomnia tend to frequently take a nap throughout the day at inappropriate times like during a conversation, work hours or even when taking a meal. These naps taken do not relieve the symptoms. Oftentimes, these individuals will have trouble waking up from their long sleep and most of the time would be confused.
Hypersomnia is divided into two categories: Primary hypersomnia and recurrent hypersomnia. Both types will manifest the same symptoms but would vary on the regularity and rate of recurrence the symptoms would occur. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) recognize primary hypersomnia, also known as idiopathic hypersomnia, as chronic excessive sleeping during daytime with all the symptoms constantly present while recurrent insomnia (also termed as recurrent primary insomnia) is intermittent daytime sleepiness that may last from one to several days and may happen again after a year or two. Although it has been clearly differentiated from narcolepsy since the former will not exhibit REM, cataplexy (loss of muscle control due to strong emotions such as laughter) and sleep paralysis.
Based on the surveys made by the National Sleep Foundation, around 40% of the population manifests hypersomnia symptoms periodically. Idiopathic hypersomnia occurs in approximately five to ten percent of the people who personal undergo check up in sleep clinics because of their excessive daytime sleepiness. There are no definite biological markers or diagnostic criteria for idiopathic hypersomnia making it quite difficult to determine its prevalence.
Signs of this sleep disorder usually appear gradually during adolescence or before 25 to 30 years of age. For idiopathic hypersomnia, the cause is unknown while recurrent hypersomnia can be caused by several factors such as:
- Kleine-Levin syndrome
- break down of the norepinephrine system
- head trauma
- injury or tumor at the CNS
- alcohol and drug abuse
- dysfunction of the autonomic nervous system
- sleep deprivation
- multiple sclerosis
- sleep apnea
- atypical depression
People with hypersomnia do not have problems sleeping at night but they do have problems awakening in the morning and staying awake during the day. They would usually sleep as long as eighteen hours but still feel tired upon awakening and would often experience disorientation.
Other symptoms of hypersomnia would include:
- excessive daytime sleepiness
- daytime naps that does not relieve sleepiness
- slow reflexes
- memory problems
- decreased energy
- mood changes
- constant yawning
To be diagnosed positive of this sleep disorder, these symptoms must be experienced for a minimum of one month causing a significant effect on the patient’s way of life. For recurrent hypersomnia, the symptoms must be experienced for no less than three days and appear intermittently for a minimum of two years.
To properly determine if the patient has hypersomnia, the physician would usually get a comprehensive sleep history and perform different tests such as Multiple-Sleep Latency Test and Sleep Study – Polysomnography (a biophysiological monitoring of changes that happens during sleep.
Since the exact cause of hypersomnia remains unknown, its treatment is based on the symptoms experienced by the individual. Mild cases usually do not require therapy. Behavioral treatment and promotion of better sleep hygiene is advocated, although these would generally have little positive effect on the condition. It is recommended that patients with this sleep disorder need to avoid intake of alcohol and caffeine.
Stimulants are prescribed to keep patients alert during day time and this would include methylphenidate, amphetamine and modafinil. Other drugs used to treat the problem are levodopa, bromocriptine, clonidine, antidepressants and MAOIs. The dosage of these drugs would depend on the needs of the patient but are controlled to prevent drug dependence and adverse reactions.
A lot of studies focused on this sleep disorder are being conducted to find a specific treatment plan that will take care of the base problem and not just on the symptoms alone.
The excessive sleeping itself is not critical but it can bring about serious problems such as increase risk for accidents (falling asleep whilst driving) or it might cause some trouble with work, school and relationships.