Cataplexy is the sudden loss of muscle tone or muscle control in response to a strong emotion. A person with cataplexy may go limp and slump over or fall. They may be unable to move. It is often triggered by strong emotions such as laughter, joy, a happy surprise, stress, or fear.1,2
Only people with Type 1 narcolepsy have cataplexy. Sometimes people with Type 2 narcolepsy, or narcolepsy without cataplexy, go on to develop Type 1 narcolepsy. When this happens, doctors believe the person probably had Type 1 all along and their orexin levels finally dropped enough for cataplexy to develop.1,3
How common is cataplexy with narcolepsy?
Cataplexy is the first symptom to appear in 1 out of 10 cases of narcolepsy. Some people may only have a few cataplexy attacks in their whole life. Others may have many attacks each day.1,2
Cataplexy develops 3 to 5 years after the daytime sleepiness began in 60 percent of people. It rarely occurs in any other condition besides narcolepsy.3
What happens during cataplexy?
Cataplexy may be mild and only impact a few muscles, causing a slight droop of the eyelids or slurred speech. In more severe attacks, the person may have a total body collapse and be unable to move or speak. However, people with narcolepsy remain awake and are aware of what is happening around them. They may keep their eyes open.1,2
Figure 1. What happens to the body during cataplexy
Episodes usually last a few minutes at the most. Some fall asleep after an attack. Even severe cataplexy by itself is not dangerous if the person can find a safe place to collapse.1,2
Mild cataplexy may be misdiagnosed as a seizure disorder if the person has no other symptoms of narcolepsy.1
Why does cataplexy happen?
During normal sleep, humans lose muscle tone during the REM stage of sleep. In people with narcolepsy, the body has lost its ability to regulate sleep and wake stages. This means the person falls quickly into a REM state in the middle of the day, losing muscle tone yet fully awake.2
How is cataplexy treated?
Only 1 in 3 people with Type 1 narcolepsy have severe enough cataplexy to need medicine to control the attacks. When needed, certain antidepressants may be prescribed, such as:4,5
- Effexor (venlafaxine)
- Prozac (fluoxetine)
- Anafranil (clomipramine)
- Vivactil (protriptyline)
XyremⓇ or XywavⓇ (sodium oxybate) may be prescribed to treat both daytime sleepiness and cataplexy. These drugs are thought to suppress the brain chemicals, or neurotransmitters, that encourage REM sleep and reduce cataplexy.4-6