Narcolepsy is a chronic and debilitating sleep disorder. Often misunderstood to be a mental illness, narcolepsy is in fact a neurological condition, and arises from a deficit of certain neurotransmitters that would normally regulate the sleep-wake cycle. Although certain symptoms may lead to a suspicion of narcolepsy, a sleep physician will often undertake investigations involving sleep electroencephalogram (EEG) and other tests to rule out sleep apnea and other disorders. Blood tests may also be used to determine whether a particular genetic marker is present, as this is common to the majority of narcoleptics, but is much less common in the general population. For the most stringent diagnostic test, a lumbar puncture may be used. A small amount of cerebrospinal fluid is removed from the patient’s spinal column, and analyzed for levels of the neurotransmitter orexin, also known as hypocretin. These chemical levels are abnormally low in narcoleptics, sometimes as far as to be undetectable.
The most well known symptom of narcolepsy is excessive daytime sleepiness. Most people have at one time or another experienced fatigue, perhaps after a late night. Narcoleptics, however, suffer overwhelming bouts of sleepiness several times a day, making it impossible to stay awake. These sleep attacks often arrive with no warning, and result in the sufferer falling asleep quite suddenly and involuntarily. Some people will be unable to work because of this, and for others working is made difficult by feelings of shame and embarrassment. Colleagues and employers often find such sleepiness difficult to understand, and think of the sufferer as lazy or disinterested.
Some sufferers also experience catalepsy. This symptom has been misdiagnosed as fainting and epilepsy, but is quite different to both. Catalepsy is a sudden loss of muscular tone, leading to jaw sagging, neck and shoulders dropping, buckling of the knees and sometimes full bodily collapse. Despite appearances – and the episode may resemble a faint – the cataleptic does not lose consciousness, but remains fully aware, able to see and hear everything around them but completely helpless to move or respond. This incapacitation usually lasts from a few seconds to a few minutes, although prolonged attacks have been documented. In narcolepsy, catalepsy is characterized by having particular triggers, often feelings of sudden or intense emotion. Laughter and anger are the most common feeling that can bring on a cataleptic attack. Sufferers often avoid social situations because of the embarrassment they feel during an attack, or for fear of being thought to be drunk.
For some narcoleptics, as well as disrupting their waking life, sleep times can also be devastating. Sleep paralysis and hallucinations can make some people with narcolepsy feel terrified to sleep. When a normal person sleeps, they drift gradually into deeper and deeper sleep, and then rise up again into a more shallow state in which dream sleep occurs. The dream phase is call REM, “rapid eye movement”, as the eyes can be seen to be darting erratically under the eyelids during this phase. In normal sleepers, the body falls into a state of paralysis in order to protect the person from acting out their dreams. However, whereas a non-narcoleptic is unaware of their inability to move, the narcoleptic may remain aware, conscious of being paralyzed and locked in a terrifying mental struggle to wake up. Additionally, REM sleep can occur at the wrong point in the sleep cycle, typically immediately on falling asleep. As the dream continues to manifest even though the person is partially awake, the sufferer is left in a limbo between sleep and wakefulness. During these periods the person hallucinates, with common themes reflecting their paralysis. Often the sufferer feels aware of a malevolent presence in the room which may seen to attack them or sit on their chest, crushing them. Because the line between sleep and wakefulness, dreaming and full consciousness, is blurred, people who have these symptoms sometimes experience profound confusion about whether some of the experiences have actually taken place or not. This may be why narcolepsy has occasionally been misdiagnosed as schizophrenia.
The fourth common symptom of narcolepsy is called “automatic behavior”. Although the narcoleptic is ostensibly awake, they are actually partially asleep and may carry out routine tasks and even conversations, only later to have no memory of anything during that period. If told something important, like an appointment, they will later deny all knowledge. This is of course in complete honestly on the part of the sufferer, as the conversation effectively happened whilst they were asleep, but sometimes families need to be patient and prepared to check that what they have said has actually got through.
As with most conditions, the exact pattern of symptoms varies from person to person, as does their severity. Narcoleptics may experience some or all of the symptoms, and the balance may change over time. Narcolepsy is under-diagnosed, and the time taken to get a firm diagnosis can be exceedingly long – decades for some patients, because of lack of awareness amongst medics. Many narcoleptics are wrongly diagnosed as being mentally ill, and may have spent years receiving entirely the wrong treatment as a result.
Traditionally, amphetamines have been used to treat excessive daytime sleepiness. More recently, advances in medication have produced alternatives that are more effective and have fewer side effects. Other medications, particularly some kinds of antidepressant, have been found to help reduce the incidence and severity of cataleptic attacks.
While some narcoleptic patients can live a more or less normal life, the condition is completely incapacitating for others, who remain unable to work and may also adopt a very isolated lifestyle to avoid catalepsy triggers. Although a genetic marker has been found which has a strong correlation with narcolepsy, it is still unclear why some people with the gene develop narcolepsy and others do not, but it seems that some other factor is also necessary. It is not common to find two sufferers in the same immediate family, and so there is no evidence that narcolepsy sufferers pass the condition on to their children.
