Depression and insomnia are strongest risk factors for frequent nightmares

A new study suggests that symptoms of depression and insomnia are the strongest predictors of having frequent nightmares.

Results show that 3.9 percent of participants reported having frequent nightmares during the previous 30 days, including 4.8 percent of women and 2.9 percent of men. Frequent nightmares were reported by 28.4 percent of participants with severe depressive symptoms and 17.1 percent of those with frequent insomnia. Further analysis that adjusted for potential confounders found that the strongest independent risk factors for nightmares were insomnia, exhaustion and the depressive symptom of "negative attitude toward self."

"Our study shows a clear connection between well-being and nightmares," said lead author Nils Sandman, a researcher in the Centre for Cognitive Neuroscience at the University of Turku in Finland. "This is most evident in the connection between nightmares and depression, but also apparent in many other analyses involving nightmares and questions measuring life satisfaction and health."

Study results are published in the April issue of the journal Sleep.

The American Academy of Sleep Medicine reports that nightmares are vivid, realistic and disturbing dreams typically involving threats to survival or security, which often evoke emotions of anxiety, fear or terror. A nightmare disorder may occur when repeated nightmares cause distress or impairment in social or occupational functioning.

The study was a joint effort of the University of Turku and the Finnish National Institute of Health and Welfare. Sandman and the research team analyzed data from two independent cross-sectional surveys of the Finnish general adult population conducted in 2007 and 2012. Participants were 13,922 adults between 25 and 74 years of age. Fifty-three percent were women. The surveys involved a questionnaire that was mailed to the participants and a health examination at the local primary health care center, where the completed questionnaire was returned and checked by a nurse. Occasional nightmares in the past 30 days were reported by more than 45 percent of participants, and 50.6 percent reported no nightmares at all.

Sleep plays a major role in mood regulation; that’s a truism that is behind every mother’s call for “time to go to bed!” But while the links between dreams and depression are well documented, the role of dreams in maintaining mental health is still one of the most confusing components in the function of sleep.

In the 1970s, psychologists noted that people suffering from depression also report more dreams than average. In fact, people who are clinically depressed may dream three or four times as much. The quality of REM dreams (also called “paradoxical sleep”) is different too: more intense emotions, more negative themes, more nightmares, and more unpleasant dreams, in general.

It’s insult on top of injury that these unpleasant dreams are often mixed with insomnia and less slow-wave sleep: that “deep” sleep that leaves us feeling restored and refreshed. Rather than waking up refreshed, the clinically depressed dreamer wakes up feeling like he has been in battle all night long and now has to get up and do it again in waking life.