Sleep paralysis, experienced by 30% globally, involves hallucinations during REM sleep. Baland Jalal, a Harvard researcher, studies its causes and terrifying experiences.

What’s a sleep paralysis demon? And other facts of the bizarre phenomenon By . Kristen Rogers. Updated Jun 8, 2025, 4:58 PM ET. PUBLISHED Jun 8, 2025, 12:00 PM ET.

Though scientists know that wake-sleep glitch is what’s happening during a sleep paralysis episode, they’re not entirely sure why. But there are several factors that can increase the risk of ...

Though scientists know that wake-sleep glitch is what’s happening during a sleep paralysis episode, they’re not entirely sure why. But there are several factors that can increase the risk of ...

Though scientists know that wake-sleep glitch is what’s happening during a sleep paralysis episode, they’re not entirely sure why. But there are several factors that can increase the risk of ...

Though scientists know that wake-sleep glitch is what’s happening during a sleep paralysis episode, they’re not entirely sure why. But there are several factors that can increase the risk of ...

This type of hallucination is a hallmark for many people with sleep paralysis. It occurs during transitions into or out of rapid eye movement, or REM, sleep, similar to a traffic jam at a busy ...

During sleep paralysis, however, “we regain consciousness before the muscles regain their freedom from REM-induced paralysis,” said Walker, who is also a professor of neuroscience and ...

Jalal’s experiences propelled him to study this phenomenon around the world. He aimed to discover the cause of sleep paralysis, he said, and why some people with the diagnosis “have these ...

Around 30% of people will experience sleep paralysis at least once. Here’s why and what you can do about it.

Though scientists know that wake-sleep glitch is what’s happening during a sleep paralysis episode, they’re not entirely sure why. But there are several factors that can increase the risk of ...