Lucid nightmares: what are they and why do they appear?

A type of dream experience full of scary elements, even though we know we are dreaming.

One of the most commonly reported experiences in sleep studies is that of having awareness and even control over one's own dream. There are even techniques and training to induce such experiences and achieve pleasurable emotions even while we sleep. But pleasurable experiences are not the only ones that usually occur.

On the contrary, there is another frequently reported experience: having lucid dreams characterized by an experience of distress and the inability to return to wakefulness. These are lucid nightmares..

We will see below what are the main characteristics of these nightmares and how they have been explained by some scientific research.

What are lucid nightmares?

We know lucid dreams to be those dreams where the person is conscious that he/she is dreaming.. They are usually positive experiences, whose content generates pleasant emotions, and whose course is easily influenced by the person dreaming. However, this is not always the case.

Lucid nightmares are a type of lucid dreaming characterized by a terrifying context and a lack of control during sleep. Like ordinary nightmares, lucid nightmares generate anguish and anxiety, but in the case of lucid nightmares an extra stressor is added: there is the intention to wake up, but there is an inability to do so.

These dreams were first described in 1911, when the Dutch psychiatrist and writer Frederick van Eeden coined the term "lucid dreaming", referring to the mental clarity during the dream state, as well as the awareness of being in such a state.

Main characteristics

In a study conducted by psychologist specializing in scientific sleep studies, Tadas Stumbrys (2018), online surveys were applied to more than 600 participants to learn about their experiences with lucid nightmares. As a result, the following common characteristics were found:

• There is awareness about the dream state..
• However there is a significant sense of lack of control.
• Intense fear persists.
• Violent characters appear who seem to have autonomy beyond the person dreaming, and even decide in a manner contrary to the wishes of the dreamer.
• There is an inability to wake up.

The same study showed that lucid dreams were frequent in more than half of the population surveyed, but lucid nightmares were reported by less than half. They further found that those who had frequent lucid dreams also had greater control over the plot of their dreams, as well as better abilities to reduce distress during lucid nightmares. That is, they perceived them as less threatening.

However, these same people also experience lucid nightmares more frequently (compared to people who do not usually have lucid dreams), and the intensity of distress experienced does not depend on the frequency of lucid dreams. Thus, although they have greater control over the sensations of distress during sleep, they are more exposed to experiencing them, they are more likely to experience them..

Why do they occur?

As we have said, the content of lucid nightmares is by definition threatening.. Sometimes it can generate near-death experiences, and these experiences can even correspond to real life upon awakening. An example is the record of cases of people who, after dreaming that someone shoots them in the heart, wake up in the middle of a myocardial attack (McNamara, 2012).

But is it a set of hallucinations? How are lucid nightmares produced? They are not strictly speaking hallucinationsThey are not hallucinations, since there is full awareness that the movements, actions, emotions, environment and characters that are being experienced are not part of the objective reality of wakefulness, although it may seem otherwise.

Lucid nightmares, like lucid dreams, emerge in the REM phase, emerge in the REM (Rapid Eye Movement) phase (Rapid Eye Movement), which means rapid eye movement, and is the phase of highest brain activity. This activity is, in fact, similar to that of the waking state, but includes a mild blockade of neurons responsible for voluntary motor regulation.

But lucid nightmares do not only occur in the REM phase, but also during the transition from REM to Non-REM sleep, or in a partial REM entry phase. Non-REM is the slow wave phase and is characterized by the introduction of deep sleep. It shows variations in brain activity and can contain hallucinations at the entrance or at the exit.

Thus, lucid nightmares occur in a state of partial sleep, where the brain does not register a complete resting activity, but neither of wakefulness.

Characteristics of brain activity in lucid nightmares.

In contrast to ordinary dreams, during the REM phase of lucid dreaming the brain shows increased activity of the prefrontal and occipito-temporal cortex, as well as the parietal lobes. These areas are the ones that are theoretically deactivated during the REM phase in ordinary dreams.

This seems to indicate that lucid dreaming is a phenomenon that does initiate in this phase (maintaining some of its characteristics, such as Muscle paralysis), but does not fully develop in REM, since it important differences at the cerebral level.

Similarly, the aforementioned brain areas can explain the state of consciousness of lucid dreams and nightmares, as well as logical thinking, decision making, and the distress generated by threatening stimuli coupled with the inability to awaken.

However, explanations about the particular content of lucid nightmares, their duration and frequency, as well as the individual experience of distress, require deeper approaches.

Bibliographical references

• McNamara, P. (2012). Lucid dreaming and lucid nightmares. Psychology Today. Retrieved September 21, 2018. Available at https://www.psychologytoday.com/us/blog/dream-catcher/201207/lucid-dreaming-and-lucid-nightmares.
• Stumbrys, T. (2018). Lucid nightmares: A survey of their frequency, features, and factors in lucid dreamers. Dreaming, 28(3), 193-204.
• Stumbrys, T., Erlacher, D., Schädlich, M., & Schredl, M. (2012). Induction of lucid dreams: A systematic review of evidence. Consciousness and Cognition, 21(3): 1456-1475.