Sleep disorders have long been cited as a symptom of depression, but new research suggests insomnia may in fact lead to depression.
A study conducted at the University of Rochester's Sleep and Neurophysiology Research laboratory concluded that depressed seniors grappling with insomnia were 17 times more likely to continue being depressed a year later than those without insomnia.
A second study at the clinic found that seniors who weren't depressed, but experienced insomnia, were six times more likely to be depressed at some point in their lives than seniors who were not insomniacs. "What we know is that insomnia is a risk factor for depression, it precedes depression and it seems to make depression resistant to treatment," said lab director Dr. Michael Perlis.
The research was recently presented at the Associated Professional Sleep Societies annual meeting in Colorado.
The first study examined more than 1,800 people over the age of 65 who had been diagnosed with severe or mild depression. The second study looked at 147 people over the age of 60 who did not have mental illness prior to the study. Of these people, 34 had persistent insomnia and 47 had a milder form of insomnia.
In the second study, researchers found that 12 of these people - 10 of whom were women - experienced new-onset depression during the year of the study, suggesting that chronic sleeplessness may trigger a higher risk of depression.
"These findings suggest that persistent insomnia may be both a precipitating and perpetuating factor of new onset and recurring depression (MDD)," the study concludes.
The investigators did not have an explanation regarding why there was a prevalence of depression-related insomnia among women. Results indicate people with persistent insomnia who tend to wake up during the night are most likely to develop depression.
The researchers said more studies are needed to explore the links between insomnia and depression, and that the sample in these studies was too small to render a meaningful conclusion.
Statistics show that about 40% of Canadian seniors struggle with sleep difficulties, and that 10% to 15% exhibit depressive symptoms.
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