Many studies have found that people with psychological disorders often also have disturbed sleep. Now a new study finds that chronic insomnia can actually increase one’s risk of developing anxiety disorders and depression.

Teasing apart the relationship between insomnia, anxiety, and depression has been a bit of a “which came first, the chicken or the egg?” conundrum. Was the depression and anxiety causing the insomnia seen in these patients or was it the other way around? This latest study by researchers in Bergen, Norway, finds that, at least for some patients, insomnia may be a precursor to mental disorders and therefore could aid in the early detection of anxiety and depression.

The study, which was published in the July issue of SLEEP, the journal of the American Academy of Sleep Medicine (AASM) and the Sleep Research Society (SRS), looked at health data collected from 25,130 adults in two surveys conducted 11 years apart. The researchers found that the participants with chronic insomnia in the first survey were more likely to also develop anxiety and depression by the time of the second survey than the participants without chronic insomnia. The results should not be generalized to assume that insomnia causes either anxiety or depression, but this study does indicate that insomnia may be a marker for an increased risk of developing these disorders.

“Chronic insomnia is a state marker of both anxiety disorder and depression,” said Dag Neckelmann, MD, PhD, of Haukeland University Hospital in Bergen and the first author on the study. “From a clinical point of view, these results imply that individuals reporting chronic insomnia, in addition to receiving adequate treatment for their sleep disturbance, should be carefully examined for the presence of anxiety disorder as well as depression.”

According to the AASM, insomnia is the most commonly reported sleep disorder. About 30% of adults have insomnia symptoms, but less than 10% probably have real chronic insomnia. It is most common in the elderly and in women.