WHO DOES NARCOLEPSY AFFECT?
Narcolepsy usually begins in childhood but until recently, was rarely diagnosed before adulthood. The average time between onset and diagnosis is still approximately 10 years, but this delay is becoming shorter as technology and awareness improve. Narcolepsy affects 0.05% of the population, and males and females tend to be affected equally. In approximately 50% of cases, symptoms start in childhood or adolescence, and common changes include weight gain, disturbed nighttime sleep, decline in school performance and social difficulties(12).
HOW DOES NARCOLEPSY AFFECT QUALITY OF LIFE?
Patients with narcolepsy show little decline in their quality of life over time, but 25% have been known to experience moderate to severe mood symptoms. Vitality and social functioning tend to decrease as daytime sleepiness increases, and symptoms appear to be worse when age of onset is later(13).
WHAT ARE THE TREATMENT OPTIONS FOR NARCOLEPSY?
Many therapies have been shown to be useful in treating the symptoms of narcolepsy despite there being no known cure(12). Non-pharmacological therapies include behaviour and scheduling modification, but these treatments are usually supplemented with medications. These can target daytime sleepiness or symptoms of cataplexy. In the past, the use of sodium oxybate, otherwise known as Xyrem, has been effective but not well tolerated by children, the elderly or patients with Obstructive Sleep Apnea. Recent studies suggest, however, that these populations can tolerate this medication if the dose is built up gradually and does not exceed 9.0g per night. Some side effects were reported, including nausea, increased snoring, paresthesia (tingling in limbs), convulsions, and enuresis (bed-wetting), however these disappeared once the dose was reduced. All patients experienced relief from cataplexy, sleep paralysis and sleep-onset hallucinations. This medication was also found to decrease daytime sleepiness, sleep latency, nighttime arousal and stage 1 sleep. In addition, slow-wave sleep and sleep efficiency increased, and these improvements persisted over time(14).
WHAT HAS RESEARCH SHOWN ABOUT NARCOLEPSY?
Research has not only investigated possible treatments of narcolepsy, but also the underlying mechanisms that cause it. The most specific genetic marker currently identified is the HLA DQBI-0602 gene. It has also been suggested that narcolepsy stems from autoimmune destruction of hypocretin-producing neurons in the hypothalamus, since decreased levels of hypocretin were found in the cerebrospinal fluid of narcoleptic patients. In response to these findings, new treatments, including immunomodulator therapy and hypocretin replacement, are being investigated(12).