Professor Guy Leschziner
Consultant Neurologist
Specialist expertise: Sleep Disorders, Epilepsy, Neurology, Headache.
Narcolepsy
Narcolepsy is a rare neurological disorder that can cause daytime drowsiness, sleep attacks and sudden muscle weakness.
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What is Narcolepsy?
Narcolepsy is a neurological disorder that causes excessive drowsiness throughout the day and sleep attacks that cause those affected to fall asleep suddenly and without warning. The condition is rare, affecting approximately 30,000 people in the UK. It can often cause distress, severely disrupt your daily life, affect your ability to work and drive, and strain your relationships.
The condition is divided into two types; type 1 and type 2.
Most people with type 1 narcolepsy will also have cataplexy (sudden loss of muscle tone) while most people with type 2 narcolepsy will not. Cataplexy causes a temporary loss of muscle control which can cause weakness in the facial muscles resulting in problems from slurred speech, through to weakness in the knees and total collapse. Cataplexy is often triggered by strong emotions, such as laughter and anger.
What causes narcolepsy?
It’s not known precisely what causes narcolepsy, but there are some factors that are thought to contribute to the condition.
Most cases of type 1 narcolepsy are thought to be down to low levels or an absence of a brain chemical called hypocretin (also known as orexin). The neurons that use hypocretin are housed in a part of the brain called the hypothalamus and are responsible for controlling and regulating sleep.
It’s thought that hypocretin deficiency is caused by the immune system attacking either the neurons that make and use hypocretin, the hypocretin itself, or both.
More research is needed, but factors that may increase a person's risk of narcolepsy or cause an autoimmune problem that can lead to the condition include a genetic predisposition (over 95% of people with type 1 narcolepsy have a genetic marker that influences how our immune system works), and exposure to a particular immune trigger such as a viral or bacterial infection.
What are the symptoms of narcolepsy?
The symptoms of narcolepsy vary from person to person and can develop over time or come on suddenly. Narcolepsy symptoms present during the daytime and at night.
The main symptoms of narcolepsy include:
- Excessive daytime sleepiness – you may feel drowsy throughout the day, which can affect your ability to concentrate
- Sleep attacks – you may fall asleep without warning, for anywhere from a few seconds to several minutes at a time
- Cataplexy – sudden temporary muscle weakness can cause jaw-dropping, head slumping, collapse of the legs, slurred speech, and double vision or difficulty focussing
- Sleep paralysis – upon waking you’re unable to move or speak for a few seconds
- Sleep-related hallucinations – when falling asleep or waking up you may see things that aren’t there
People with narcolepsy may also experience other symptoms as a result of the condition. These can include:
- Restless or broken sleep
- Depression
- Automatic behaviours
- Difficulty maintaining concentration or attention
Narcolepsy is usually diagnosed through consideration of your symptoms, by ruling out other sleep-related conditions, and through analysis of your sleep through formal sleep studies. In certain cases, your specialist may also recommend a test to measure your levels of hypocretin in your spinal fluid.
What are the treatment options for narcolepsy?
Narcolepsy is not curable, but there are treatments that can help manage the symptoms and lessen their impact on your daily life. Treatment usually involves medications, but changes to your lifestyle can also help.
Medications commonly used to manage narcolepsy include:
- Modafinil
- Amphetamine-based stimulants
- Sodium oxybate
- Antidepressants
- Other wake-promoting agents
Lifestyle changes that may help include:
- Taking frequent, short planned naps
- Following a strict bedtime routine, e.g. going to bed and waking up at the same time every day
- Maintaining good sleep habits, e.g. keeping your bedroom cool and dark
- Avoiding alcohol and sedative drugs
- Joining support groups
- Talking to mental health professionals