Nightmares: what are they and why do they appear (causes)

We spend a good part of our lives sleeping, which is not surprising considering the large amount of energy that we must replenish to cope with the day to day. However, there are times when the sleep stage, which we usually associate with calm and well-being, turns into a hell from which we desperately try to get out.

And is that what we know as nightmares has come to have such a strong impact on humanity that they have long ceased to be a simple unpleasant experience that we experience individually to become a source of all kinds of mythologies or, directly, the definition of what we we want to run away. In fact, we use the word "nightmare" to refer to any highly unpleasant or traumatic experience, equating the real to what only happened in our heads.

However… What are nightmares and what causes them? Let's see.

• Related article: "What are dreams for?"

What are nightmares?

Nightmares are a state of anxiety and agitation that appears at the moment of dreaming, often associated with images and sensations that cause fear, sadness or any other negative emotion, in such an intense way that the interruption of sleep is generated.

Thus, it is considered that a bad dream does not become a nightmare if it does not causes us to wake up or reach a state of consciousness between sleep and wakefulness.

This sudden break with sleep comes easily, as the REM phase, which is the one that occurs while we sleep and dream (that is, when when sleeping we are simultaneously in a state of consciousness directed towards the interior, not towards the exterior), is the stage of sleep that most closely resembles waking, attending to the activation patterns of neurons in that moment. A little "push" can take us back to the real world.

• Related article: "The 5 phases of sleep: from slow waves to REM"

Why does a nightmare appear?

Like everything that surrounds the study of dreams, there is little that is known for sure about the causes of nightmares. But there are several things on which there is consensus.

The first thing to know is that it is highly unlikely that there is a single cause that explains the existence of nightmares. This, which is applicable to practically any psychological process, in the case of nightmares is It reflects on the effect that various elements have on the frequency of appearance of these unpleasant experiences. For example, leading a busy and stressful lifestyle makes them appear more often, and addiction to alcohol has a similar effect, making what we dream about tends to be more unpleasant and anxious.

On the other hand, there is another thing for sure about nightmares: Sigmund Freud was wrong about its origin. For the father of psychoanalysis, the nightmare is what happens when a part of the unconscious emerges into the dream state without we are able to repress its contents, for which we have been forced to keep those ideas, memories or beliefs. The state of anxiety produced by the fact of beginning to see what we want to continue to ignore makes us wake up to make these types of revelations stop.

Why do we know that this does not happen? Among other things, because the theories in which Sigmund Freud was based to provide this explanation to the phenomenon are not valid, since they are based on speculation about case studies. There are no parts of our mind that try to hide certain contents and prevent them from emerging to consciousness, simply there are contents that at a certain moment are not relevant enough to make our attention reach they.

• You may be interested: "Nightmares and night terrors: differences and similarities"

They are useful?

Bearing in mind that Freudian ideas about nightmares do not serve to understand the nature of this kind of experience... What are nightmares for? Some theories suggest that nightmares are useless, and are a consequence of evolution that has not been promoted by natural selection as an advantageous trait; they are simply there, and they are harmless enough that the genes that make them possible do not disappear over the generations.

Other theories, on the other hand, do attribute a utility to nightmares. Specifically, they point out that their presence on a day-to-day basis can make us prepare for stressful events, maintaining a certain state of anxiety that will be useful in the short term to overcome concrete obstacles, and that appear when there is something in our forecasts that worries us. In this way, the nightmare would be a kind of mental training to enter a state of alert more easily and, therefore, react quickly.

However, in some cases the possible usefulness of nightmares would not compensate for the damage they cause, so we enter a vicious cycle of stress and anxiety that negatively affects our health. In any case, most people are not significantly affected by the appearance of nightmares, since they do not usually occur in a very followed and, despite the fact that in many cases what is seen in them is very disturbing, it is not experienced with the same harshness with which one would live if it were real.