A woman leaning her head on her hand with her eyes closedCan sleep duration predict whether someone will struggle with anxiety or depression? Research from the EMGO Institute for Health and Care Research in Amsterdam, The Netherlands examined the relationship between sleep duration and depressive and anxiety disorders. They found that both long (10 or more hours) and short (six or fewer hours) sleep durations can predict chronic depression and anxiety and that insomnia, although a sleep disorder, did not predict the presence of either depression or anxiety.

The researchers evaluated data from 1,069 patients with an average age of 42.7 who were diagnosed with depression or anxiety according to the DSM-IV diagnostic criteria. Additionally, 59% of the group had insomnia, defined as a Women’s Health Initiative Insomnia Rating Scale score of nine or more. After the initial assessment, the researchers did a follow-up evaluation two years later. At the time of the second assessment, 61% of the patients had persistent depression and/or anxiety. The patients were asked to report on how long they sleep per night.

The findings indicate that longer or shorter than average sleep duration is correlated with chronic depression and anxiety. However, insomnia itself was not a predictor of depressive or anxiety disorders. The results were adjusted for socioeconomic characteristics, chronic disorders, psychotropic medication, and symptom severity.

Patients who slept ten or more hours nightly were approximately 2.5 times more likely to have persistent depression or anxiety than those who slept seven to nine hours. Long sleep duration was also correlated to a nearly three-fold increase in risk in chronic depression and anxiety.

Patients sleeping less than six hours nightly were more 1.6 times more likely to have persistent depression, but when adjusted for symptom severity, this risk was not as significant. A 1.5-fold increase in risk for chronic depression was associated with short sleep duration.

“Our study adds significant information on the impact of sleep disturbances on the course of psychopathology. In clinical practice, routinely asking for sleep duration might identify subjects at risk for a chronic course,” state lead researcher Josine van Mill and colleagues.

This research is published in the Journal of Clinical Psychiatry.

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