Are you sleepy? Greater than half of the US population experience sleep difficulties and yet only a handful of adults report having discussed sleep problems with their physician. Insufficient sleep, medications, psychiatric illness, and a variety of medical disorders may result in daytime hypersomnolence. Alternatively specific sleep disorders may have profound impact on an individualís health and quality of life.

Narcolepsy is a lifelong disorder that interferes with the ability to maintain normal wakefulness. Symptoms including excessive daytime sleepiness profoundly impact social functioning and quality of life. Narcoleptics may display reduced performance at school or work resulting in decreased earning, fewer promotions, and more dismissals. Life itself may be endangered by a greater incidence of accidents. Approximately 1 in 2000 people in the US is affected making narcolepsy about as common as multiple sclerosis. Although onset commonly occurs between 15 and 30 years of age, narcolepsy affects all ages. Unfortunately diagnosis is frequently delayed by an average of 10 years or missed completely due to inadequate doctor-patient communication or attributing symptoms to depression, epilepsy, drugs, or other medical illness.

Excessive daytime sleepiness that cannot be relieved but for a short time with any single period of sleep is present in essentially all narcoleptics. Cataplexy, a partial or complete loss of muscle tone provoked by emotion or simply the anticipation of emotion, is the symptom most specific to narcolepsy occurring in 60% to 100% of patients. While laughter is the most frequent and joking the most specific trigger of cataplexy, anger, startle, surprise, and fatigue are other common triggers. Other frequent symptoms include vivid dream-like hallucinations experienced just before sleep or upon awakening often in conjunction with a feeling of paralysis, fragmented nighttime sleep, and purposeful activity performed without recollection.

Minimal criteria for the diagnosis of narcolepsy are at least 3 months of recurrent daytime somnolence and the presence of cataplexy. Nonetheless a thorough sleep evaluation is often required not only to confirm the diagnosis in the absence of unequivocal cataplexy but also to exclude other sleep disorders that might account for daytime sleepiness or more importantly are often present in addition to narcolepsy. Such sleep disorders include but are not limited to sleep apnea and periodic limb movements syndrome. Specific to the evaluation, standardized questionnaires might be used to assess the severity of daytime sleepiness. Objective testing in a sleep lab complements such information. Diagnosis commonly focuses on the multiple sleep latency test (MSLT) performed as a series of naps the day following overnight polysomnography used to assess nocturnal sleep. The presence of pathologic daytime sleepiness characterized by early sleep onset and the early intrusion of REM or dream sleep observed on an MSLT are consistent with the diagnosis of narcolepsy.

Nonpharmacologic therapy for narcolepsy involves structuring sleep and naps. Psychosocial support may also be helpful. Pharmacologic therapy employs stimulants to promote wakefulness and antidepressants in treatment of cataplexy. Several newer agents are now available for addressing excessive somnolence, cataplexy, and other narcolepsy-associated symptoms.

Should you experience excessive sleepiness at inappropriate times or any of the symptoms described herein, you are urged to discuss these with your physician. You could have narcolepsy or another sleep disorder. Snooze you may lose.

-Brian J. Gilmore MD

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