Narcolepsy is a persistent sleep disorder characterized by excessive daytime drowsiness, leading to frequent and abrupt episodes of falling asleep. This condition can significantly disrupt a person’s daily life and routines.
In some cases, narcolepsy is accompanied by a condition called cataplexy, which involves a sudden loss of muscle control, often triggered by strong emotions, particularly laughter. Narcolepsy is typically categorized into two main types:
- Type 1, which includes cataplexy
- Type 2, which does not involve cataplexy.
Unfortunately, narcolepsy is a lifelong condition with no known cure. However, individuals can manage its symptoms effectively through medications and lifestyle adjustments. Additionally, a strong support system from family, friends, employers, and teachers can greatly assist people in coping with this disorder.
- Excessive daytime sleepiness: People with narcolepsy can unexpectedly fall asleep at any time, even during activities like working or talking with friends. This can be particularly dangerous while driving. These episodes can last from a few minutes to half an hour, and after waking up, they may feel temporarily refreshed but soon become sleepy again. Daytime sleepiness makes it difficult to concentrate and stay alert.
- Cataplexy (sudden loss of muscle tone): Cataplexy is a condition associated with narcolepsy where individuals experience slurred speech or temporary muscle weakness, sometimes causing them to collapse. It is often triggered by intense emotions, including positive ones like laughter or excitement. However, emotions such as fear, surprise, or anger can also lead to cataplexy episodes.
- Sleep paralysis: Sleep paralysis is a common experience for those with narcolepsy. It occurs when individuals are unable to move or speak while falling asleep or upon waking. Although brief, it can be unsettling. Sleep paralysis can happen independently of narcolepsy.
- Hallucinations: People with narcolepsy may experience hallucinations during sleep paralysis or even without it. These can be vivid and may involve seeing things that aren’t real, such as a stranger in the room. These hallucinations may occur as they fall asleep (hypnagogic) or upon waking (hypnopompic).
- Changes in REM sleep: Normally, REM sleep, where most dreaming occurs, starts 60 to 90 minutes after falling asleep. However, individuals with narcolepsy tend to enter REM sleep much more quickly, often within 15 minutes of falling asleep. REM sleep can also occur at unconventional times during the day.
Other characteristics: People with narcolepsy may also have other sleep disorders like obstructive sleep apnea, REM sleep behavior disorder (acting out dreams), or insomnia (difficulty falling or staying asleep).
If you experience excessive daytime sleepiness that interferes with your daily life, it’s essential to consult with a healthcare provider.
Narcolepsy can be categorized into different types, each with its own underlying causes, most of which are linked to the hypothalamus—a brain region responsible for regulating sleep–wake cycles.
- Type 1 narcolepsy: Type 1 narcolepsy is mainly associated with a shortage of a chemical called orexin (also known as hypocretins), which is produced by neurons in the hypothalamus. In people with narcolepsy, orexin levels in the cerebrospinal fluid (a protective fluid around the brain and spinal cord) are very low or undetectable. Research suggests that this occurs due to an autoimmune problem, where the immune system mistakenly attacks the neurons producing orexin. A specific genetic mutation (HLA–DQB1*06:02) is found in about 90% to 95% of individuals with type 1 narcolepsy. However, not everyone with this mutation develops narcolepsy, and it can also run in families. Certain infections, like H1N1 influenza and strep throat, can trigger narcolepsy by affecting the immune system.
- Type 2 narcolepsy: The exact causes of type 2 narcolepsy are not fully understood, but they may be similar to those of type 1 narcolepsy. This type may involve less severe damage to orexin–producing neurons or issues with orexin transmission in the brain.
- Secondary narcolepsy: Secondary narcolepsy is rare and can result from damage to the hypothalamus due to factors such as head injuries, strokes, brain tumors, or other medical conditions. In some cases, narcolepsy can be linked to inherited conditions like autosomal dominant cerebellar ataxia, narcolepsy, and deafness (ADCADN) or autosomal dominant narcolepsy, type 2 diabetes, and obesity.
Only a few known risk factors for narcolepsy exist, such as:
- Age: Narcolepsy develops between the ages of 10 and 30. The young adults in their late teens and early 20s are more prone to experience it.
- Gender: Male have higher risk in developing the condition than female.
- Family history: If the patient has a close relative who has narcolepsy, their risk of developing it is 20 to 40 times higher.