David N. Neubauer, M.D, associate director of the Johns Hopkins Sleep Disorders Center, answers patients’ questions about the interrelationship between insomnia and mood disorders. He begins with the chicken-and-egg question…
Q. Do sleep disorders cause mood disorders or vice versa?
A. That’s not an easy question to answer. It is a relationship that goes both ways. There is very clear evidence that when a person is experiencing a mood disorder, particularly a major depressive episode, he or she is highly likely to suffer from sleep disturbance -- most often, insomnia. In fact, insomnia is so expected that it’s part of the diagnostic criteria in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV).
When surveying people who are depressed, we find that 80% experience sleeplessness, and it’s not only the classic early-morning awakening associated with depression, but rather all the possibilities, including difficulty falling asleep and middle-of-the-night awakenings. There is also the issue of severity: The more depressed someone is, the more likely it is that he or she will have insomnia. The converse is true, too. If a person suffers from insomnia, over time it creates a risk for developing a mood disorder such as major depression. There are several excellent observational studies that demonstrate the link between insomnia and the future risk of developing a mood disorder. The link is evident as quickly as one year after an episode of insomnia, and can last as long as decades.
Regardless of which comes first, there is a lot of comorbidity (coexistence) between insomnia and depression, and it’s important to address both conditions. One of the greatest challenges in depression is to find the medication (or combination of medications) that will alleviate the depression as well as the insomnia.
Q. What is the connection between insomnia and anxiety disorders?
A. Researchers have documented the frequency of insomnia among specific subcategories of anxiety disorders, such as panic disorder, generalized anxiety disorder, post-traumatic stress disorder, and even social anxiety disorder. Data indicate that insomnia is just as common among people with anxiety disorders as people with depressive disorders. It is an equally strong link.
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