I'm trying to build up a database of mental health resources on my other website, Lorien Psychiatry. Every time I post something, people here have made good comments, so I want to try using you all as peer review.

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Summary: Nightmares happen when the process of dream generation is biased by ambient stress - or sometimes for other reasons. Anything that decreases stress, increases comfort while sleeping, and deepens sleep quality will also improve nightmares, including colder, darker rooms, less indigestion, and treating any comorbid psychiatric or medical conditions. If that doesn’t work, several kinds of therapy - including Image Rehearsal Therapy, Systematic Desensitization, and Lucid Dreaming - may be helpful. Prazosin is the standard anti-nightmare drug, and can be taken at doses from 1 - 12 mg, but watch out for side effects.

1. What causes nightmares?

Nobody really knows why we dream. Modern neuroscience suggests that the brain processes data by creating predictive models, then double-checking them against reality. We experience the predictive models, not reality - although the double-checking process is so fast that they usually match well enough to be the same for all practical purposes. When we can’t double-check with reality - for example because we're asleep and not receiving sense-data - then the predictive models go out of control and become essentially random. This results in us having kind of random experiences.

Anxiety is a bias for the brain to interpret information in a threat-related manner. Instead of generating completely random data, the anxious brain, when deprived of sense-data, generates data with a bias towards threatening stimuli. A sufficiently threatened, stressed, or traumatized person will naturally have more threatening dreams.

Other people have nightmares even when their overall mood is good and they have no history of trauma. I have no good explanation for this; it might be biological, or due to some kind of sleep problem.

2. How can I reduce nightmares through lifestyle changes?

Dreams occur during REM sleep, a very light stage of sleep on the border of wakefulness. Although it's natural to have some REM sleep, anything that prevents deep sleep and pushes you towards more light sleep instead will give you more (and worse) dreams.

So: pain, discomfort, heat, caffeine, bright lights, alcohol, stimulant medications, a noisy environment, an uncomfortable bed. Of these, heat is an especially common culprit . Use windows, fans, and A/C, but also consider getting lighter sheets, wearing less clothing, and taking off your socks (it's socks in particular a surprising amount of the time!). Digestion is another common culprit; try not to eat too soon before bedtime, and try not to eat foods that make you feel bloated and give you indigestion.

Check your medications and supplements. Any stimulating medication can give you nightmares. But so can some antidepressants, sleeping pills, and almost anything else. Even humble melatonin can cause nightmares in susceptible people, as can (too much) of some B vitamins. If you're taking any of these, ask your doctor if it's okay to stop them for a week or two and see if your nightmares go away during that time.

You have a circadian rhythm: a time when your body expects to be asleep. If that doesn't correspond to the time it's actually asleep, then sleep will be light and low-quality, in exactly the way that causes nightmares. The most common way this works is people sleep late into the morning, and find the last few hours of their sleep are filled with nightmares. If that happens to you, you might want to shift your bedtime earlier. Sometimes the nightmares will go away entirely. Other times people's circadian rhythms are disturbed, and going to sleep at (what other people would consider) a normal time causes nightmares. See the section on melatonin for more.

Your body has an optimal amount of muscle tension/relaxation it expects when sleeping. If this is off, you can have nightmares. You can relax your muscles more by exercising at different times, taking warm showers before bed, or doing progressive muscle relaxation exercises / meditation before sleep. Occasionally someone will have nightmares because they've done too many of these things and their muscles are overly relaxed.

Sleep apnea is a condition where your airway closes while you’re sleeping, making you temporarily suffocate. You wake up before dying, but usually fall asleep again almost immediately without realizing this is happening. This puts a lot of stress on your body and makes you feel worse in many, many ways, but one of them is nightmares. Reasons to think you might have sleep apnea (a relatively common condition) include: being overweight, snoring, and feeling very tired when you wake up in the morning even though you got a full night sleep. If that’s you, and you also have nightmares, get tested for sleep apnea. If the apnea is treated, the nightmares will probably go away, and you’ll also feel much better in other ways.

Finally, anything that makes you less stressed will reduce nightmares. If you're in a terrible job that you hate, quitting will reduce nightmares. If you're in a terrible relationship that you hate, breaking up will reduce nightmares. And so on to all the other categories of stressful things.

3. What therapies and medications are good ways to reduce nightmares?

Any therapy or medication that helps with anxiety or trauma will probably help with nightmares. That means typical anxiety medications (except that some of these, like SSRIs, can cause nightmares as a side effect in unlucky people) and typical trauma-focused therapies. I would recommend that anyone who thinks they’re suffering from trauma (eg PTSD) try a trauma-focused therapy like EMDR before trying to address nightmares directly, unless the nightmares are overwhelmingly worse than all their other trauma symptoms.

But in terms of treating nightmare specifically, here’s the headline image of Randomized controlled trials of psychological and pharmacological treatments for nightmares: A meta-analysis:

The numbers in the blue square are effect size, ie how good the treatment is. Higher numbers are better, 0 means it doesn’t work at all, and negative means it makes things worse.

We’ll look at a few of these further: Desensitization and LDT, the two highest-performing therapies. IRT, the best-studied therapy. And prazosin, the highest-performing medication.

3.1: What are therapies for nightmare disorder?

In systematic desensitization therapy, you and your therapist pick out scary elements of your nightmares. For example, if you always dream of being chased by wolves, that would be the element. Then the therapist asks you to imagine relatively weak, innocuous version of the scene while awake, and teaches you relaxation techniques you can use to defuse the emotional impact. Once the weak versions lose all emotional impact, you move on to stronger versions. Eventually, everything about being chased by wolves seems boring and absent of emotional valence to you, and your nightmares either go away on their own or lose their nightmarish quality.

In image rehearsal therapy, you and your therapist identify common nightmare plots, then rehearse changes to those plots which defuse their emotional content. For example, if you always dream of being chased by wolves, you imagine the wolves shrinking until they are adorable puppies, and then you play fun games with those puppies. You repeat this image in various ways, so many times that it gets etched into your brain as the natural completion of any scene involving wolves. Then when you have a nightmare, your brain “auto-completes” it with the wolves turning into puppies and playing games with you. The nightmares lose their nightmarish quality and eventually go away.

(I’m not sure how you do these therapies if your nightmares don’t have recurring themes. If any therapists understand this, please email me at scott@lorienpsych.com. Some sources suggest that if you do these practices with enough different nightmares, your brain learns the meta-lesson that nightmares in general aren’t scary or end with pleasant content, and you don’t have to keep doing the same therapy for ever new theme.)

In lucid dreaming therapy, you learn how to lucid dream - that is, how to “wake up” inside your dreams so that you’re fully conscious and in control. Once you’ve reached lucidity, you’re no longer afraid - obviously if you have a recurring nightmare of being chased by wolves, and now you’re being chased by wolves, and you can’t remember going to a national park or anything, it must be a dream. You can then take control and turn the wolves into puppies or shift the scene to a day on the beach or do whatever else you want. This therapy is difficult - it takes a lot of practice to lucid dream - but lucid dreaming is a pretty interesting skill even aside from nightmare prevention, and it could be worth it.

3.1.1: How do I access these therapies?

It’s pretty tough. Most therapists won’t be trained in these. Image Rehearsal Therapy is probably the most common, but still hard to find. If you search “‘image rehearsal therapy’ [YOUR AREA]” sometimes you’ll find somebody. Otherwise, ask any doctors or therapists you know and see if they know anybody.

Can you do these on your own from a manual or course? I can’t find any officially-studied ones, but there are a few unofficial ones. Dr. Justin Havens has a sort of minimum viable teach-yourself-Image-Rehearsal-Therapy video here. And here’s a paper aimed at clinicians describing IRT in enough detail that somebody could probably do it on themselves if they understood.

Stephen LaBerge’s Exploring The World Of Lucid Dreaming (Amazon link, free copy with unclear legal status) is a good introduction to lucid dreaming in general, but it’s long and detailed and a lot of work. I don’t know of anything simpler aimed at nightmares in particular. Some people will find lucid dreaming interesting enough that they’ll be willing to put in the many months of work it will take to make it work well; people looking for a specific fix for this specific problem will probably find other methods simpler.

3.2: What medications work for nightmares?

The standard of care is prazosin, an alpha-blocker. Here is a good review study.

The correct dose of prazosin is somewhere between 1 - 12 mg, different for everybody. Many doctors will give up at 2 or 3 mg, which is much less than 12 and which I think is a mistake.

That having been said, prazosin can be annoying to get on to, especially at higher doses. Side effects include dizziness, faintness, lack of energy, low blood pressure, and fainting when standing. Most of these don’t matter, because you’re going to take it immediately before going to sleep. But if you get up in the middle of the night (for example, to go to the bathroom), you might find yourself feeling dizzy or fainting when you stand up. To solve this problem, stand up very slowly and carefully until you know how prazosin affects you. It usually affects people most the first few times they take it on any specific dose, so be especially careful then. In certain rare cases, prazosin can make people urinate in their sleep. This is rare enough not to be worth worrying about, but if it does happen, it’s the prazosin and you don’t have to worry about it being anything else.

There are various people who should be more careful with prazosin or not take it at all, including people with low blood pressure or people on beta-blockers. Your doctor will tell you more about this.

Clonidine is another drug that is very similar to prazosin. It probably also works for this indication, but it’s less tested and probably works about the same; I don’t think there’s any reason to prefer it unless someone has very specific prazosin intolerance.

3.2.1: Are there any supplements or natural products that will help with nightmares?

Any supplement that helps with anxiety or sleep - so theanine, silexan, magnesium, etc - may have some positive effect.

Some studies show that very large doses of glycine (~3 grams) seem to directly improve sleep quality, which should have positive effects on nightmares. You would probably have to get a lot of glycine powder and pour it in a smoothie to get this much nightly, but it might be worth a try.

4: Where can I learn more?

The Best Practice Guide To The Treatment Of Nightmares In Adults is a good source. It will mostly repeat what I said here, but in more depth and with better explanations. It also discusses a few other potential treatments.