Circadian Health Glossary

Narcolepsy

Narcolepsy is a chronic neurological sleep disorder. It affects the balance between waking and sleeping. It is characterized by excessive daytime sleepiness, sudden loss of muscle tone, known as cataplexy, hallucinations, and disrupted sleep patterns.

Causes of Narcolepsy

The exact cause of narcolepsy is still unknown. However, researchers believe that it is a result of both genetic and environmental factors. People with narcolepsy are known to have low levels of a brain chemical called hypocretin, which helps regulate wakefulness and sleep. This deficiency may be due to an autoimmune disorder, where the body’s immune system mistakenly attacks and destroys the cells that produce the chemical.

Types of Narcolepsy

There are two types of Narcolepsy, type 1 and type 2:

• Type 1 is characterized by the presence of cataplexy. It is less common among individuals suffering from this disorder.

• Type 2 can be distinguished by the lack of cataplexy. It is sometimes referred to as “common narcolepsy.”

Symptoms of Narcolepsy

Narcolepsy symptoms usually develop for a few months and last for a lifetime. Some of the symptoms include:

• Excessive Daytime Sleepiness (EDS) – Feeling extremely tired and sleepy despite sufficient rest, impacting daily alertness.

• Cataplexy – Sudden loss of muscle tone, leading to weakness or collapse. Commonly it is triggered by intense emotions like laughter, surprise, or anger.

• Sleep Paralysis – Temporary inability to move or speak during waking up or falling asleep.

• Hallucinations – Vivid and occasionally frightening experiences during transitions between sleep and wakefulness.

• Disrupted Nighttime Sleep – Frequently waking up during the night. It contributes to overall sleep disturbances in individuals with narcolepsy.

Related Definitions

Circadian Health Excessive Daytime Sleepiness (EDS)Sleep Narcolepsy sleep