Narcolepsy (sometimes also mistakenly written as narcalepsy) is a chronic, life-long, neurological sleep disorder that usually appears in your late teens or early twenties and is characterized initially by excessive daytime tiredness.
What causes narcolepsy?
The causes of narcolepsy remain something of a mystery, although two recent studies have suggested that there is a strong possibility that it arises in people who are deficient in two related chemicals normally found in the hypothalamus – an area deep inside the base of the brain that regulates many functions, including sleep.
These chemicals are known as hypocretins or orexins and studies indicate that more than ninety percent of narcolepsy sufferers either lack, or show extremely low levels, of these chemicals.
For some considerable time now it has been known that there is a connection between narcolepsy and a specific type of human leukocyte antigen (HLA), which is a genetically determined protein found on the surface of white blood cells, forming part of your body’s immune system. The exact nature of this connection has, however, not been understood.
Today it is suggested that HLA may play an important role in an autoimmune disease that is responsible for destroying the body’s hypocretins, or orexins. In other words, a disorder within the immune system causes the body to attack itself (in this specific case it’s own hypocretins or orexins), rather than to perform its normal function of attacking foreign infections.
Whether or not this will prove to be the cause of narcolepsy is yet to be seen, but those studying the condition are satisfied that they are now close to isolating the cause.
Who suffers from narcolepsy?
No particular group is more susceptible to narcolepsy than another and it is seen in both men and women of all ages. The first signs of narcolepsy normally appear during your teenage years, or in your early twenties, but cases can arise in children as well as in adults in later life.
One particular characteristic of this disease it that it is often several years after the onset of the disease (typically about 15 years) before it is diagnosed. It is also one of today’s most commonly under-diagnosed conditions. For example, although about 50,000 sufferers in the United States are diagnosed with narcolepsy, it is estimated that the true number of narcoleptics is closer to 200,000.
[Side Note: The term narcoleptic can be used to refer to a person who suffers from narcolepsy and also to a soporific drug which produces an uncontrollable desire to sleep.]
What are the symptoms of narcolepsy?
There are two main narcolepsy symptoms:
- Excessive Daytime Sleepiness (EDS).
- An abnormal pattern of rapid eye movement (REM) sleep.
To understand this better let’s just digress for a moment to consider a normal sleep pattern, which consists of five stages.
- Stage 1. During stage 1 sleep you drift in and out of sleep and can be easily awakened. Your eyes move very slowly and muscle activity begins to slow.
- Stage 2. As you enter stage 2 sleep (which accounts for about half of your total sleep time) eye movement stops and your brain activity slows.
- Stage 3. In stage 3 sleep your brain activity continues to slow and the brain begins to produce what are known as delta waves.
- Stage 4. During stage 4 sleep (which together with stage 3 sleep are referred to as “deep sleep”) your brain produces mainly delta waves and there is no eye movement or muscle activity.
- Stage 5. In a normal sleep patter you will reach stage 5 sleep after about 60 to 90 minutes. Stage 5 sleep is also known as REM sleep and it is during this cycle, which lasts for about 30 minutes, that you dream. Your heart rate increases, your blood pressure rises and your breathing becomes more rapid, irregular and shallow. Your eyes jerk rapidly in all directions during REM sleep and your limb muscles become temporarily paralyzed. If you are woken during this cycle you will often remember bizarre and illogical tales.
This 5 phase cycle of sleep, which normally last about 90 to 120 minutes, is repeated several times during the course of the night and, as it does so, the length of time spent in REM sleep gradually increases as the time spent in stage 3 and stage 4 sleep reduces. By morning therefore you are spending the majority of your time moving between stage 1 and 2 sleep and REM sleep.
In cases of narcolepsy both the order and length of your sleep cycles are altered, with REM sleep appearing shortly after falling asleep, rather than following a period of deep sleep.
In addition, some of the characteristics of REM sleep also appear at abnormal times, often giving rise to narcolepsy being referred to as a REM sleep disorder.
In particular three specific characteristics of REM sleep appear as narcolepsy symptoms:
- Cataplexy. Seen in about two thirds of all cases of narcolepsy, cataplexy can appear at the same time as excessive daytime sleepiness, or may not be seen until several years after the onset of the disease.Cataplexy is a temporary loss of muscle control that can range from relatively minor symptoms, such as weakness at the knees, to a complete collapse causing you to fall to the ground. Episodes can last from just a few seconds to several minutes and can occur occasionally or several times every day. You remain conscious throughout these episodes, but are normally unable to speak.Cataplexy episodes are normally triggered by events associated with strong emotions such as laughing, surprise or anger.
- Hallucinations. About half of all narcolepsy sufferers will experience vivid dream-like images, known as hypnagogic hallucinations, as they drift into sleep. Often these images can be quite frightening, not least because you’re still partially conscious in this stage between wakefulness and sleep, but are unable to control these images.The nature of the images seen often gives rise to feelings ranging from anxiety, through fear, to absolute dread and it is not uncommon for these episodes to lead you to believe that you are suffering from some form of mental illness.
- Sleep paralysis. Again about half of all narcolepsy sufferers experience sleep paralysis in which there is a brief loss of muscle control as you drift into, or out of, sleep. In this still partially conscious state between being awake and asleep you retain a general awareness of your surroundings, but are unable to move or to speak.Sleep paralysis can appear at the same time as a hypnagogic state and, for some sufferers, the resulting feelings of terror can appear overwhelming.
These ‘major’ symptoms can appear all at the same time or may develop over several years. Some may not appear at all. Indeed only about a quarter of all sufferers experience all four of this disorder’s major symptoms. The one narcolepsy symptom that is always present however is excessive daytime sleepiness.
In addition to these main symptoms, sufferers may experience:
- Automatic behavior. Here you find that you carry out routine tasks without being aware that you are doing them, or having any recollection afterwards of having carried them out. This often extends to behavior that appears to have little purpose and can also be accompanied by talking in a meaningless fashion and making little or no sense. This behavior is effectively being carried out in a state that is halfway between wakefulness and sleep.
- Disturbed sleep. Waking repeatedly during the night.
- Difficulty concentrating.
- Loss of memory.
- Double vision.
How is narcolepsy diagnosed?
In the minority of cases where all four of the major symptoms are present, narcolepsy sleep disorder is relatively easy to diagnose. In other instances however possible sufferers are normally asked to keep a ‘sleep diary’ for a period of two to three weeks, recording not only details of their sleeping positions and habits, but also such things as their diet and any medication that they take. They will then normally attend a sleep clinic where they will stay overnight, with their sleep activity being recorded. The following day, they will often be asked to undergo further tests. The two most commonly used tests are:
- Polysomnogram. A polysomnogram test measures a number of your body’s activities as you pass through the various stages of sleep, so that these can be compared to results expected from someone experiencing a normal pattern of sleep. Those bodily activities recorded include:
- Electrical brain activity. Electroencephalogram.
- Electrical heart activity. Electrocardiogram.
- Muscle movement. Electromyogram.
- Eye movement. Electrooculogram.
- Respiration. Oral thermister or nasal pressure transducer.
- Multiple Sleep Latency Test. This test is normally carried out immediately following a polysomnogram and tests the time taken to fall asleep during the day.
Four or five naps will be scheduled throughout the day at about two hourly intervals and the time taken to fall asleep will be measured. In a normal subject the time taken to fall asleep will be somewhere between ten and twenty minutes. In the case of a narcolepsy sufferer, however, sleep will usually occur within less than five minutes.
It had previously been thought that narcolepsy could be diagnosed using a blood test to look for the presence of human leukocyte antigen (HLA). The type of HLA associated with narcolepsy is not, however, unique to the condition and, accordingly, HLA typing should not be used for diagnosis.
What is the treatment for narcolepsy?
At present there is no cure for narcolepsy, which is a chronic and life-long condition. It is possible, however, to treat the symptoms with a combination of medication and behavioral therapy.
The objective of any insomnia treatment is to keep you as alert as possible during the day and to minimize the symptoms of the associated cataplexy, hallucinations and sleep paralysis.
- Medication. Two separate forms are medication are normally used in narcolepsy treatment – one to reduce daytime sleepiness and the other to counter the effects of cataplexy, hallucinations and sleep paralysis.
- Stimulants. Stimulants are normally prescribed to counter daytime sleepiness. The range of possible narcolepsy drugs is far too long to list them all here, but perhaps the two most commonly prescribed are Ritalin (Methylphenidate) and Provigil (Modafinil).
- Ritalin. Ritalin is one of a number of central nervous system stimulants traditionally used in cases of narcolepsy but unfortunately, in common with other drugs in its class, Ritalin also increases activity in other parts of the nervous system, often giving rise to undesirable side effects. These include headache, irritability, nervousness, gastrointestinal problems and further disturbed nighttime sleep.In addition, narcolepsy drugs of this nature can loose their effectiveness if used over extended periods of time.
- Provigil. Provigil is a relatively new drug which is rapidly replacing Ritalin, and other central nervous system stimulants, as the drug of choice for treating daytime sleepiness in narcolepsy.Unlike other narcolepsy medications, Provigil does not interfere with the hormones associated with sleep and so does not result in disturbed nighttime sleep. It also causes far less nervousness and anxiety than many other alternative drugs and has fewer side-effects in general. The main side-effects are headache and nausea, but these tend to be short-lived.
- Anticataplectic medication. This is the general term used for narcolepsy medication prescribed not only to counter the effects of cataplexy, but also to reduce the symptoms of hypnagogic hallucination and sleep paralysis.There are five main categories of anticataplectic medication commonly used in narcolepsy treatment today.
- Tricyclic Antidepressants. These are used to slow down the central nervous system and include such drugs as Tofranil (Imipramine) and Anafranil (Clomipramine). There are a range of side effects associated with this class of drugs, some of which can be extremely serious, and care should be exercised if using this form of medication
- Selective Serotonin Reuptake Inhibitors (SSRIs).These are again designed to slow down the central nervous system and include such drugs as Prozac (Fluoxetine). SSRIs display fewer side-effects than tricyclic antidepressants.
- Monoamine Oxidase Inhibitors (MAOIs). These drugs, which include Eldepryl (Selegiline), block monoamine oxidase B, an enzyme that degrades dopamine and is believed to play a role in narcolepsy. There can be some serious side-effects associated with these drugs, especially if used in conjunction with other antidepressant drugs. Further complications can arise from the interaction with certain foods.
- Gamma hydroxybutyrate (GHB). This particular drug, commonly referred to as Xyrem (Sodium oxybate), has been in use in Europe for some time now, but has only recently gained FDA approval for use in the United States (July 2002). Side effects, which tend to be mild, include nausea, headache, dizziness, urine leakage, and sleepwalking
- New Antidepressants. Two relatively new antidepressants are also being prescribed for cases of narcolepsy. The first, Edronax (Reboxetine) is known as a selective noradrenaline reuptake inhibitor (NARI) which is a unique form of antidepressant showing encouraging results in early use. The second, Effexor (Venlafaxine), is a selective serotonin and norepinephrine reuptake inhibitor (SSNRI) that has again shown promising results in early use.
- Behavioral Therapy. As with any sleeping disorder it is extremely important to take steps to ensure that you give your body the best possible opportunity to enjoy a good night’s sleep. By looking closely at your lifestyle and making changes to your habits and daily routine where necessary, you can make a substantial difference to the quality of sleep that you enjoy.In the case of narcolepsy sleep disorder it is particularly important to see that you get a full night’s sleep (seven to eight hours is a good target to aim at) and that you go to bed and get up at the same time each day, following a sound routine.Unlike the behavioral therapy for many other sleep disorders, such as insomnia and sleep apnea, you should, however, also schedule two or three short naps of about fifteen minutes into your daytime routine, to help in keeping you as alert as possible during the day.Narcolepsy sleep disorder can create problems in both your personal and professional life and many of these will have to be faced head on. Family, friends and colleagues can all help, provided you let them, and you must be aware of, and act within, your limitations. Examine carefully just how narcolepsy effects your life and make changes to your lifestyle and routine as required.If you find that you’re particularly irritable in the late afternoon, then perhaps this is a good time to spend some time on your own rather than risk upsetting loved ones or colleagues.Similarly, if you’re particularly tired around lunchtime, then avoid driving the car in the middle of the day.
Narcolepsy effects each sufferer differently and you will need to find a method of coping that suits you, your family and friends and work colleagues best.
By understanding just how narcolepsy effects your life and by taking a few simple steps to adapt your lifestyle, you’ll find that you can improve your quality of life, in many cases, quite dramatically.