Nightmares tied to anxiety and insomnia in heart patients

"Health professionals should ask patients if they experience bad dreams as a warning sign for depression, anxiety, or trouble sleeping," said Dr. Kohno. "Psychological disorders and insomnia are linked with the development and progression of heart disease and upsetting dreams could be a clue that patients need extra prevention efforts."

"Our study shows strong associations between depression, anxiety, insomnia, and bad dreams in patients with heart disease," added study author Dr. Takashi Kohno of Keio University School of Medicine, Tokyo, Japan. "As this was an observational study, it cannot determine the cause-effect relationship, but it may be bidirectional. In other words, depression, anxiety and insomnia may cause nightmares, and nightmares could lead to depression, anxiety and insomnia."

Previous research has shown that frequent nightmares are associated with sleep and psychological disorders in the general population. This was the first study to investigate this relationship in patients with heart diseases. It also examined whether heart medications were connected with unpleasant dreams.

The study included 1,233 patients admitted with various heart diseases to Keio University Hospital. The average age was 64 years and 25% were women. Nightmares, sleep and psychological characteristics were assessed with self-reported questionnaires and sleep-disordered breathing (when breathing stops and starts during sleep) was measured using overnight pulse oximetry (a measure of blood oxygen levels).

Nearly 15% of patients had at least one nightmare per month, and 3.6% had at least one nightmare per week (defined as frequent nightmares). Women were more likely to have frequent unpleasant dreams compared to men. Some 45.9% of patients reported insomnia, 18.5% had depression, 16.9% had anxiety, and 28.0% had sleep-disordered breathing.

Frequent nightmares were not associated with heart medications and sleep-disordered breathing, but were linked with depression, anxiety, and insomnia. Patients with weekly bad dreams were five times more likely to be depressed (odds ratio [OR]=4.61; 95% confidence interval [CI]=2.03-10.48), five times more likely to be anxious (OR=5.32; 95% CI=2.36-12.01), and seven times more likely to have insomnia (OR=7.15; 95% CI=2.41-21.22).

Dr. Kohno said: "The prevalence of nightmares and frequent nightmares in the general population, reported by other groups, is similar to the experience of heart patients in our study. We showed that in people with heart disease, women are more likely than men to have persistent bad dreams - this also mirrors findings in the general public. The strong associations among frequent nightmares, insomnia, and psychological disorders we observed reflects prior research in healthy people, suggesting that these relationships could be universal regardless of the presence of heart diseases."

He concluded: "Nightmares may be an alert for underlying psychological or sleep problems that should be addressed to avoid new, or worsening, heart problems. Healthcare professionals should include a question about bad dreams in their assessments.