Neuroscientist Patrick McNamara offers one of the most startling accounts of nightmares that I have ever heard. 

In this video for The Well, the Boston University associate professor of neurology first offers the benefits of REM sleep — its association with creative capacities and religious consciousness in humans—and then proceeds to dig into its darker aspect: nightmares. 

First, he observes something I had not appreciated, which is that people with a certain neurobiology are more prone to have nightmares, and that this tendency seems to be related to having more dissociative episodes (periods of being disconnected from reality) when awake. 

Second, he observes that nightmares featuring “demonic agents”—creatures regarded by the dreamer as demons—have been observed in some people to follow a chilling pattern. 

This is the part that has stayed with me ever since I first watched it.

For dreamers particularly vulnerable to nightmares, McNamara says, it begins with a dream with a demon in a room. The demon is in a corner of the room—the same room as the dreamer. It does not move, but is nevertheless frightening. 

A week later, the dream recurs. This time, the demon is not across the room, but next to the bed. 

The following week, the nightmare returns. This time, the demon has become aware of the dreamer. It approaches the bed where the person is having the nightmare. 

In fright, the dreamer puts up barriers. Week after week, the demon comes closer. Eventually, McNamara says, these efforts to thwart the being fail. 

People experiencing such a sequence of nightmares “need to get clinical help” before the demonic agent breaks through the barriers because, he observes, “in many cases the demonic agent is out to possess the individual’s consciousness.” 

In case studies of demonic possession, he says, the possessions “invariably occur after a series of nightmares. Finally the demonic nightmare possesses the individual’s consciousness, and they wake up in a possessed state, and you need exorcism rituals to get rid of the demonic agent.” 

This description of nightmares gives me nightmares. 

The whole video is well worth the watch–and the phlegmatic way in which McNamara relates this knowledge adds (for me) to the hair-raising effect. 

Watch to the end to find out a positive dimension that many cultures revere about people who bear the burden of suffering nightmares. One of my favorite videos (I have many) that we have produced on The Well.

This post draws upon a series of videos produced by The Well, a publication and video channel produced by the John Templeton Foundation and BigThink.