What's Up With Nightmares?

Summary

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Short Wave – "What's Up With Nightmares?"

Host: Regina Barber (NPR)
Guest: Dr. Michelle Carr, Sleep Scientist at University of Montreal, author of Nightmare Obscura
Release Date: November 21, 2025
Episode Length: ~15 minutes

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Episode Overview

This episode explores the science behind nightmares and dreams, focusing on why they occur, how they're connected to our emotions, and what tools and therapies might help people deal with distressing dreams. Host Regina Barber interviews Dr. Michelle Carr, whose new book Nightmare Obscura details the mechanisms of dreaming, the benefits (and potential harms) of nightmares, and cutting-edge research in dream engineering.

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Key Discussion Points & Insights

1. Common Nightmares and Dream Themes

• Regina Barber opens by sharing her recurring nightmare of losing control in a car, setting the tone for a personal and relatable discussion.
• Dr. Carr reassures Regina:

  “That is a very common dream theme. I have it all the time as well.” (Michelle Carr, 00:54)

• Other frequent dreams include teeth falling out, flying, falling, or discovering new rooms. (01:18)
• Insight: Such dreams may stem from the body's lack of sensation during sleep—manifesting as perceived loss of control.

2. The Mystery of Nightmares and Dreaming

• Despite extensive research, the exact reason we dream or have nightmares remains somewhat elusive.
• Dr. Carr highlights the importance of distinguishing the roles of sleep versus dreaming in mental health:

  “We're only just beginning to uncover whether dreaming and the way that we feel during sleep is significant in our health as well.” (Michelle Carr, 01:45)

• Purpose: The episode’s goal is to demystify why nightmares happen and how they might benefit or hamper us.

3. Sleep Stages and Dreaming

• Dr. Carr explains the four sleep stages (03:39):
  • Stage 1: Transition between awake and asleep; fleeting, strange images may appear.
  • Stage 2: Deeper, more stable; disconnected from external stimuli.
  • Stage 3: Deep, slow-wave sleep; minimal, brief, often forgotten dreams.
  • REM (Rapid Eye Movement): Most vivid, emotional, and sensory dreams—brain activity resembles wakefulness.

  “REM sleep is the stage when we also have the most vivid and emotional and sensory dream experiences.” (Michelle Carr, 04:34)

4. Sleep’s Role in Emotional Processing

• Referencing research in Nightmare Obscura, Dr. Carr discusses how sleep helps us process stressful experiences.
• Study example: Participants watched embarrassing videos, then felt shame; after sleep, their emotional response decreased. (05:04)

  “It's helping us let go of a lot of the distress that we accrue during the day.” (Michelle Carr, 05:26)

• Insight: Sleep helps dissociate emotional distress from the memory itself, promoting adaptation and readiness for new challenges.

5. Nightmares: Causes and Functions

• Nightmares are often linked to past trauma or periods of high stress.

  “It's almost like the memory is too intense and the emotion is so strong that it kind of disrupts sleep.” (Michelle Carr, 07:19)

• Occasional nightmares or bad dreams may actually represent healthy emotional processing; persistent, intense nightmares can be harmful.
• Analogy: Dr. Carr compares nightmares to a “mental autoimmune reaction”—your mind attacking itself with memories. (07:00)

6. Neuroscience of Nightmares

• Nightmares seldom occur in sleep labs; being observed may make people feel safe. (08:34–08:57)
• Brain regions active in dream-emotions mirror those in waking life.
• People with frequent nightmares exhibit less activation in the brain’s frontal (emotion-regulating) areas when distressed:

  “They’re less able to regulate and to control and to manage their emotion… this is occurring both during REM sleep... and wakefulness.” (Michelle Carr, 09:52)

• Implication: Poor dream-based emotion regulation can spill into daytime life.

7. Treating Nightmares

• Imagery Rehearsal Therapy (IRT):
  • Exposure to the nightmare script (write/talk about it without avoidance).
  • Then, rewrite the dream with a more positive or empowered outcome.
  • Visualize the new script before sleep each night.

  “Over time, this decreases nightmare frequency... and improves symptoms overall.” (Michelle Carr, 11:38)

• Key benefit: Greater sense of control over dreams and reduced distress.

8. Sleep Engineering & Lucid Dreaming

• Lucid Dreaming: Being aware that you’re dreaming and gaining control over the narrative.

  “Even if you just start to have more agency in your dreams, that can be beneficial... more awareness in your dream, even if you’re not fully lucid.” (Michelle Carr, 12:27–13:17)

• Dream Engineering: Using intention and visualization before bed to influence dreams.

9. Exciting New Technologies

• EEG Headbands: Wearable tech that detects sleep stages in real time, possibly enabling in-sleep interventions.
• App Innovations: Some devices deliver stimuli (e.g., gentle vibrations) when signs of arousal/nightmare are detected to disrupt distressing dreams.

  “They might present a vibration stimulus which awakens you a little bit and it interrupts the nightmare as it’s occurring.” (Michelle Carr, 14:31)

• Implication: Technologies could enable personalized, immediate responses to nightmares at home—not just in the lab.

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Notable Quotes & Memorable Moments

• On common nightmare themes:

  “Teeth falling out or flying or falling or finding new rooms in my house.”
  (Michelle Carr, 01:18)

• On sleep and emotional reset:

  “After a night of sleep, if you think about that same problem, it almost seems completely manageable.”
  (Michelle Carr, 05:26)

• On the adaptive value of (occasional) nightmares:

  “These are all reflecting what is an adaptive process of sleep and of dreaming, which is you’re trying to work through these stressful or negative experiences.”
  (Michelle Carr, 08:01)

• On the neuroscience of nightmares:

  “There’s actually less activation in their frontal areas of their brain when they are experiencing emotional distress.”
  (Michelle Carr, 09:57)

• On dream intervention tools:

  “It's a dream, so you can do whatever you want, really.”
  (Michelle Carr, 11:15)

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Timestamps for Important Segments

• 00:54 — Common nightmare themes
• 03:39 — Walkthrough of sleep stages, dream-rich REM
• 05:04–05:26 — Sleep’s role in emotional processing, embarrassing video study
• 07:00–08:23 — Nightmares as self-attacks, mental autoimmune analogy
• 09:52 — Brain differences in people prone to nightmares
• 10:45–12:11 — Imagery Rehearsal Therapy explained
• 12:27–13:30 — Lucid dreaming and agency in dreams
• 13:41–14:58 — Dream tech: EEG headbands, wearable interventions

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Takeaway

The science of nightmares is still evolving, but understanding when bad dreams become problematic—and the tools we can use to manage them—can make the world of sleep a little less frightening. Occasional nightmares may be part of healthy emotional processing, but persistent distress deserves attention. New research and technology are making it easier than ever to understand and even influence our dreams.

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For deeper dives, check out Michelle Carr’s book Nightmare Obscura or previous Short Wave episodes on sleep and melatonin.**

Transcript

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[Regina Barber]

You're listening to Short Wave from npr. You come home from work, you're exhausted. You finally get into bed and your head hits the pillow. And then the next thing you know, your car is barreling out of control on the highway. You're going around that turn, but you're in the backseat. You can't reach the brakes. At least that's my reoccurring nightmare. But when I told that to Michelle Carr, she wasn't phased.

[Michelle Carr]

That is a very common dream theme. I have it all the time as well. I think it's just related to our physical body being like not really receiving any sensation of the car pedal. So the dream is like going out of control.

[Regina Barber]

As a sleep scientist at the University of Montreal, her job is basically watching people sleep. So when it comes to dreams and nightmares, she's pretty much heard it all.

[Michelle Carr]

Teeth falling out or flying or falling or finding new rooms in my house.

[Regina Barber]

Michelle is the author of the new book called Nightmare Obscura. In it, she explores the science of dreams, nightmares, even something called dream engineering, where people are able to influence their own dreams while they sleep. But why we dream or get nightmares is still a bit mysterious for scientists.

[Michelle Carr]

We know so much about how important sleep is for our health, but we're only just beginning to uncover whether dreaming and the way that we feel during sleep is significant in our health as well.

[Regina Barber]

And since humans spend somewhere around one third of our lives asleep, we had to know more. So today on the show why your nightmares go bump in the night. We dive into the science of our sleeping life with Michelle Carr and make nightmares a little more known, a little less scary. Hi, I'm Regina Barber and you're listening to Shortwave, the science podcast from npr.

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[Regina Barber]

MICHELLE Sleep happens in cycles. So can you just walk us through the four different stages of sleep?

[Michelle Carr]

Sure, yeah. When we first start to fall asleep, there's this stage where we're still a little bit awake and we just start entering a stage where our brain waves start to slow down. And that's pretty obviously called stage one sleep. It's just a really brief period of sleep onset, a transition. And already in stage one sleep, we can start to have really bizarre thoughts or images that appear in our mind. And stage two is when our brain waves slow down a bit more. It's a much more stable sleep state and we're really disconnected from the sensory environment. And gradually we move into a deeper state. Stage 3, or slow wave sleep, where there are really a lot of very slow waves throughout the brain. And this is the state with the least amount of dreams. Our dreams are really short and brief and maybe thought like when we're in stage three sleep or we don't remember anything at all. And then the fourth stage is REM sleep. It's called REM because our eyes are moving, rapid eye movements, and our body and our mind are actually quite active. During rem, our brain is even it looks very similar to wakefulness. We have a lot of really high frequency activity in the brain. And REM sleep is the stage when we also have the most vivid and emotional and sensory dream experiences.

[Regina Barber]

It seems like, at least for me and many people, like there's emotional component to sleep. And in your book Nightmare Obscura, you write about a study you love where participants watched embarrassing videos of themselves singing and then their brain showed signs of shame. But that changed after a night of sleep. What does that tell you about, like the importance of sleep?

[Michelle Carr]

Yeah, I think this is maybe something that a lot of people can relate to that, you know, we all go through different stressful experiences during the day and at night, just before sleep, you might be worrying about, you know, an argument you had or like really stressed about, you know, something that happened during the day. And then after a night of sleep, if you think about that same problem, it almost, it seems completely manageable. And this is one of the functions of sleep. It's helping us to essentially, in a way, let go of a lot of the distress that we accrue during, during the day. Like all of the emotions that get activated during the day, we kind of are, are able to let go of them during a night of sleep. And even for memories that we have, we. We let go of the emotion that's attached to them. So it helps us to adapt and to be better able to manage anything that might come up the next day.

[Regina Barber]

It kind of sounds like exposure therapy.

[Michelle Carr]

Yeah, I think that there is a similarity there in that you're. But I think one of the keys about sleep and what makes it different from maybe like being exposed to stressors in waking life is that there's actually a very physiological component that the brain and the body are in a specific state where during sleep we're able to reactivate emotional memories. Like the amygdala is active, but our physical body is actually subdued in certain ways. So we think that's really essential to being able to strengthen and to hold onto and to store important memories, but to let go of the kind of stress and arousal that's attached to them.

[Regina Barber]

And then that makes me think of nightmares, which mostly seem to happen in that fourth REM sleep stage when our amygdala, which deals with fear, is more active. In your book, you call nightmares almost like a self attack. Like there's this mental autoimmune reaction. Is that what's happening? Like why do we have them?

[Michelle Carr]

Yeah, I guess part of that analogy is that the source of nightmares is something that we have experienced. And so it's. We do see that nightmares are specifically very highly correlated with past experiences of trauma or with adversity. They occur a lot more during periods of stress. It's almost like the memory is too intense and the emotion is so strong that it kind of disrupts sleep anyways. It causes the body to become really aroused and you just, your sleep is interrupted and you wake up in a state of distress.

[Regina Barber]

Are there any benefits of nightmares, you know, like this mental autoimmune reaction that we have in our minds?

[Michelle Carr]

I mean, I think there's a benefit to bad dreams in general and even to occasional nightmares. And I think if nightmares are occurring occasionally or if you're having bad dreams, I think these are all reflecting what is an adaptive process of sleep and of dreaming, which is you're trying to work through these stressful or negative experiences that you've had.

[Regina Barber]

So where do scientists see nightmares in the brain? Is this a different like part of our brain than pleasant dreams? I'm just so interested, like where do they live?

[Michelle Carr]

Yeah, there's actually not too many actual recordings of people having nightmares in the sleep lab. This is one of the kind of curious things about studying nightmares or any sleep disorder, actually, that patients what. Who have nightmares or other sleep disorders frequently at home, they very rarely have episodes in the lab. So.

[Regina Barber]

Wow. They feel safe in the lab.

[Michelle Carr]

I know we think. I mean, that's one of the theories. But in general, you know, we have some evidence that experiencing emotion or memories and dreams, it seems like it's. It's the areas of the brain that are active in waking life. But there is some work on kind of the brain basis of nightmares and nightmare disorder. And one thing that we have seen is that people who have nightmares potentially have a difference in how their brain regulates emotion. And specifically, we know that sleep is important for emotion regulation. And it specifically helps this connection between basically frontal or prefrontal areas of the brain, which are responsible for helping us to control and to regulate our emotion and their connection with the amygdala, with our emotional arousal centers. So in people who have nightmares, what we see is that there's actually less activation in their frontal areas of their brain when they are experiencing emotional distress. So in principle, we think this means they're less able to regulate and to control and to manage their emotion. And that this is occurring both during REM sleep when emotion regulation is really maintained. And then this spills over into wakefulness as well, making them. They'll have a harder time managing and dealing with stress and waking life because of this.

[Regina Barber]

And speaking of stress, when you're awake, you mentioned in your book that there's a point where nightmares can become harmful to overall health. So what are some methods researchers use to treat nightmares?

[Michelle Carr]

The main methods to treat nightmares are imagery rehearsal therapy is the most common therapy, and there's just a lot of other variations of that. And it's basically a technique, what's called rescripting a nightmare's content, because nightmares very often have very recurring themes. So if somebody has a nightmare of a tidal wave or a nightmare of being chased, they tend to have these themes that recur over time. And it's almost like this script that's learned in your mental imagery. And so imagery rehearsal therapy works with first just a little bit of exposure to the nightmare, like kind of being more comfortable with looking at your nightmares, talking about them, writing them down, and not being so aversive to them, and then changing the nightmare in some way. So you write a slightly new script or change something. So it's not so scary or make yourself more powerful. And it's a dream, so you can do whatever you want, really. And then before sleep, you visualize this new, more pleasant or more satisfying dream. Visualize that for 10 to 20 minutes, minutes before sleep each night. And over time, this decreases nightmare frequency. It makes people feel less distressed by their nightmares, and it improves symptoms overall.

[Regina Barber]

And this is the sleep engineering you were talking about, right? Like trying to do things to affect your dreams? I have had personal experiences where I feel like I can alter things within my dream. Is that normal? Have you studied that as well?

[Michelle Carr]

Yeah, that's definitely very common. And that moves a little bit into what's called lucid dreaming, which is where you become aware of the fact that you're dreaming while you're still asleep. So, of course, if you're fully aware that you're in a dream, you can control yourself and your own actions, but you can even potentially change the dream environment, the scenery. Yep, yeah, exactly. You can change things around you. But one thing that I find really interesting is even when you're not fully lucid, like, even if you. Even if you just start to have more agency in your dreams, that can be beneficial. So kind of like you said, maybe you don't realize it's a dream, but you have this thought like, oh, maybe I don't need to be afraid of this thing that's chasing me, or, oh, maybe I can just change the scene or move into a different room or something. You start to have essentially just more of this choice and awareness, more awareness in your dream, even if you're not fully lucid. And that can be helpful for people.

[Regina Barber]

One of the final chapters of your book, you talk about exciting new technologies and methods to study dreams. Can you give us some of those highlights of these new technologies?

[Michelle Carr]

Yeah, there's already, of course, a lot of apps and ways to just record your dreams and follow, like, maybe different visualizations you can practice before sleep to influence dreams. But in our lab, we're pretty interested in new wearable EEG technologies. So these are, like, wearable headbands that you can use during sleep. They're getting better at being able to detect sleep stages in real time. And this means that we would be able to not only measure someone's sleep at home, but potentially use these types of wearable headbands to actually potentially influence sleep as it's occurring, using different types of sensory stimulation, like, to shake you.

[Regina Barber]

Out of a nightmare or to like, soothe you.

[Michelle Carr]

Yeah, there is one, I think, app and wearable technology that's designed to maybe detect when you're basically when you're showing signs of arousal during sleep, which they're using as kind of a proxy for maybe you're experiencing a nightmare. And when they detect this state of arousal, they might present a vibration stimulus which awakens you a little bit and it interrupts the nightmare as it's occurring. In theory.

[Regina Barber]

You'Ve made me think about my dreams even more. So thank you, Michelle, for talking to us today.

[Michelle Carr]

Yes, thank you for having me. It was a pleasure.

[Regina Barber]

If you liked this episode, you might want to check out our episode on Melatonin and avoiding jet Lag. We'll link to them in our episode notes. This episode was produced by Rachel Carlson and edited by our showrunner, Rebecca Ramirez. Tyler Jones checked the facts and Kwesi Lee was the audio engineer. Beth Donovan is our vice president for podcasting. I'm Regina Barber. Thank you for listening to Short Wave from npr.

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