Two new studies show that insomnia, far from being a symptom or side effect of depression, may instead precede it, making some patients more likely to become and remain mentally ill.
One paper was presented today at the 19th Annual Meeting of the Associated Professional Sleep Societies (APSS) in Denver, and the other will be published shortly in the Journal of Behavioral Sleep Medicine.
In recent years, researchers established that insomnia and depression are linked, but struggled to determine which came first. Many experts believed that depression caused insomnia until new drugs arrived that improved depression, but not insomnia. The idea that insomnia could be a contributor to, or predictor of, depression gained credence.
The study presented today at APSS is the first to establish that insomnia prolongs bouts of sadness, hopelessness and loss of interest in life activities that characterize major depression, making patients less likely to recover. Specifically, the study found that depressed patients with insomnia were nearly 11 times more likely to still be depressed at six months than those sleeping well, and 17 times more likely to remain ill after a year. Data were drawn from Project IMPACT, a study in late-life depression that enrolled 1,801 men and women aged 65 years or older.
"The new findings are especially significant because they suggest that targeted treatment for insomnia will increase the likelihood and speed of recovery from depression," said Michael Perlis, Ph.D., director of the University of Rochester Sleep and Neurophysiology Research Laboratory (URSNRL), and an author the studies presented at APSS and published in the journal. Wilfred Pigeon, Ph.D., asst. director of the sleep lab, was lead author of the study presented today.
Perlis is the lead author of the upcoming journal article, which found that elderly patients with insomnia (and no history of depression) are 6 times more likely to experience an initial episode of depression than individuals without insomnia. The results from this study also suggest that the risk is especially high in elderly women, and in individuals who experience one of three types of insomnia. Most at risk for first-time depression were patients with severe "middle insomnia," a pattern where patients wake up frequently during the night, but eventually fall back to sleep each time.
Elderly patients are a focus of research because two million older adults have a depressive illness, and five million more experience less severe forms of depression. As a group, they account for 18 percent of all suicide deaths despite representing just 13 percent of the population. At the same time, studies have found that 42 percent of elderly adults have trouble sleeping.
The two studies reflect a larger effort underway at the URSNRL, which recently received $2.3 million in grant support from the National Institutes of Health to investigate whether treatment for insomnia can reduce major depression and improve pain tolerance in patients with chronic back pain. Clinical studies are underway to determine whether or not cognitive behavioral therapy for insomnia leads to fewer, shorter and less severe bouts of depression, as well as to improved pain tolerance.
In addition to the studies mentioned above, the sleep lab is also conducting clinical trials on insomnia secondary to cancer and a variety of treatment studies on both the medical treatment and cognitive behavioral therapy of insomnia. While many studies are conducted on an outpatient basis, some studies are conducted in the laboratory, which features an apartment-like suite with four bedrooms, two baths, offices and a control room with electrophysiologic equipment to monitor sleep patterns.
Study participants receive a free physical exam and an analysis of how to improve their sleep, as well as free treatment.
For more information or to enroll in a sleep study, please call 585-475-3379 (585-4-sleepy) or visit www.sleeplessinrochester.com.