What would be the effects of losing the ability to dream?

Question

In my fantasy setting, dreams are located in what could be called a parallel dimension - commonly known as "The Void". Some people are able to develop powers related to the Void through long training (mainly teleportation).

I am thinking of adding a shortcut to aquiring those powers by having your dream "popped" and dislocated into the Void. My main concern here is that there have to be some sort of drawback to this method. One of the consequences I have thought of, is permanently losing the ability to dream.

I have searched a bit but it seems that this condition doesn't exist in the real world. You may not remember your dreams but paradoxical sleep will still happen.

So I'm wondering what if I completely removed paradoxical sleep? What could be the consequences on mind and body?

Answer 1

This is more of a bio-psychology question, and I'll admit off the bat I'm a bit rusty. So be patient with me.

Dreaming only happens during REM-sleep (Rapid Eye Movement). This is where the brain tries to 'reboot' the mind, to help you feel 'rested'. The thing about dreams in and of themselves, they are... strange. They are basically (or at least typically) fractions of your day (week, month) scattered across the canvas of your semiconscious mind (here I mean the 'aware' part of your brain). So you 'relive' parts of it in various ways as a means of helping you 'digest' those memories.

This typically works out in strange ways (hence my calling them strange). So if you're having an erotic dream, a sensation (a touch, a glance, a look in someone's eyes) could be superimposed onto someone or something else. For example, someone at work/bar/library is flirting with you, that gets superimposed on your sibling/mother/whoever during your dream, because you were already 'thinking' about them in that segment of the dream.

Now, the reason I describe all that is to show the clear difference between 'dreams' and REM sleep. You would need to figure out if this 'cost' is the REM sleep (which is biologically needed to feel rested) and 'dreaming' (which is an psychological process of 'processing your day'). The difference (as I understand it) would be one means you're going to be cranky and tired for life (REM) and the other means you won't process your day quite the same way and could become mentally unresponsive to certain (or all) stimuli (dependent on other factors and/or how extreme you want the price to be).

I'd advise you research the psychological studies done on sleeping and dreaming, and there've been quite a few. A good starting place, if ever there was one.

Answer 2

No one actually knows why we dream, or even really why we sleep ^{Ob xkcd 203, 1345} .

Dream deprived individuals sometimes develop psychological symptoms including anxiety, paranoia, and a significant increase in appetite. Some describe hallucinations during the day. Dream deprived individuals seem to dream for longer when the allowed to again. The studies however suffer from small sample sizes and the impossibility of double blinding.

Depriving individuals of dream sleep is less damaging than depriving them of deep sleep, which can have drastic effects, even death in animal subjects.

A lot of these experiments were done in the 1960s take a look at a paper: Sampson 66. Which describes the results of an experiment with 4 individuals.