Narcolepsy is the incurable tendency to fall asleep suddenly during the day. The attacks are sudden and uncontrollable and may occur in the middle of a conversation of whilst eating a meal. Other possible symptoms include temporary paralysis on falling asleep or waking up with visual hallucinations or agitated. Because narcolepsy starts in adolescence, the symptoms are often mistakenly put down to this stage of life. Those who fall asleep is class may be called lazy or blamed for staying up late at night; they may be ridiculed or bullied in school. Consequently sufferers often also develop low self-esteem, depression and have problems socializing and developing relationships.
In 1996 a gene was found for susceptibility to narcolepsy which suggested that it might be an immune system disease. However environmental factors clearly play a strong role in its development, as only 20% of the time do both identical twins with the gene develop the condition. This may be associated with initial triggers such as infections with measles or mumps, accidents or hormonal changes during puberty. Scientists have since pinpointed a neuro-transmitter called hypocretin that may be involved in triggering a narcoleptic attack. It would appear that people with narcolepsy have a deficiency of this brain chemical. The current treatments are stimulant drugs, including some amphetamines.
Narcolepsy is not a common condition and precisely how many people are affected in not known. The prevalence of the disorder is comparable to that of multiple sclerosis or Parkinson's disease, and only a small fraction of sufferers have been diagnosed. Obtaining a proper diagnosis is difficult with the average time between onset of the disease and diagnosis of 15 years. A rough estimate is one or two people in every two thousand are affected, with men men and women being affected equally. Approximately four out of five people with narcolepsy also suffer with a condition called cataplexy, which produces sudden loss of muscular control.