Insomnia and depression are a predictor for nightmares, according to new research conducted in Finland.
The study, published in the journal Sleep, had two goals. First, it wanted to find out if factors associated with frequent nightmares could be reproduced in a large population sample. It also wanted to examine whether there were previously unreported factors that can cause nightmares or make them more frequent.
The American Academy of Sleep Medicine define nightmares as “usually coherent visual dreams that seem real and get more disturbing as they unfold and cause you to wake up.” Nightmares often involve imminent physical danger and can provoke a range of negative emotions including anxiety, terror, embarrassment and disgust.
For the study, the researchers analyzed data taken from two independent cross-sectional surveys of the Finnish adult population conducted in 2007 and 2012. Questionnaire data were available for 13,922 participants aged 25-74 years and included nightmare frequency along with other items related to overall health and lifestyle.
A total of nearly 4% of participants reported having frequent nightmares during the previous 30 days, compared with 45% reporting occasional nightmares and the remaining reporting no nightmares at all.
The researchers found that nearly one third of participants with severe depressive symptoms reported experiencing frequent nightmares, as did more than 17% of participants with frequent insomnia.
After analyzing the data further, the researchers concluded that the strongest independent risk factors for frequent nightmares were insomnia, exhaustion and “negative attitude toward the self” – a symptom of depression.