Scientists have revealed the secret of nightmares

People with high levels of waking stress are more likely to experience negative emotions in their dreams. At the same time, strategies for coping with daytime stress do not appear to change these nighttime reactions. The results have been published in the scientific journal Dreaming.

Psychologists have long described the connection between everyday life and dreams through the so-called continuity concept: experiences, thoughts, and feelings from the waking state carry over into dream content. If a person has faced significant stress during the day, the same anxiety and fear are highly likely to catch up with them at night.

Psychologist Jonas Mathes from Heidelberg University in Germany, together with colleagues, recruited 65 volunteers aged 17 to 61 for the study — predominantly female students. Participants completed a questionnaire assessing stress in various areas of life — finances, pressure at work or school, health — and also indicated which coping strategies they used: adaptive (positive thinking, support from loved ones) or maladaptive (alcohol and cigarettes).

Over the course of 14 days, participants kept a dream diary. Each morning they recorded whether they remembered a dream, rated the intensity of emotions on a scale from zero to three, and noted specific feelings: fear, sadness, anger, joy, surprise, and others. At the end of each entry, they decided for themselves whether the dream they had was a nightmare.

Over two weeks, 276 dream descriptions were collected. Surprise and joy appeared most frequently in them, yet negative emotions were present in 39% of cases. Approximately 11% of dreams were classified by participants as nightmares. Their frequency was found to be associated with negative experiences — particularly with anger — and inversely proportional to joy.

Waking stress reliably predicted negative emotions in dreams: the higher the everyday stress, the more intense the distressing experiences in dreams turned out to be. Interpersonal and financial anxieties penetrated nighttime narratives most strongly — uncertainty in relationships with loved ones and money problems.

The researchers had hypothesized that adaptive coping strategies would weaken negative dreams, while maladaptive ones would intensify them. However, the influence of both turned out to be statistically insignificant. Neither support from loved ones, nor positive thinking, nor alcohol, nor cigarettes changed the emotional tone of dreams. How a person copes with stress during the day, it appears, does not affect how that stress manifests at night.

The limitations of the study should be taken into account: the research relies on self-reports filled out in the morning from memory, which may distort the picture. The sample is small and consists predominantly of young female students recruited online. The frequency of nightmares turned out to be low, and maladaptive coping was measured only through alcohol and cigarettes. Future studies could expand the range of strategies and focus on people who suffer from frequent severe nightmares.