Insomnia may significantly increase the risk that older adults will be unable to shake off depression, researchers say.
For the study, the investigators analyzed data on nearly 600 people over age 60 who visited primary care centers in New York City, Philadelphia and Pittsburgh. All had some level of depression.
Compared to patients whose sleep improved, those with worsening sleep problems were about 28 times more likely to be diagnosed with major depression at the end of the 12-month study.
Patients whose sleep worsened also had nearly 12 times the odds of minor depression and were 10% more likely to report having suicidal thoughts, according to the Johns Hopkins Bloomberg School of Public Health study.
The report was recently published online in the journal Sleep.
Compared to patients whose sleep improved, those with persistent, but not worsening, insomnia were more likely to have lasting depression. But their risk was not as high as patients whose sleep got worse.
"These results suggest that, among older adults with depression, insomnia symptoms offer an important clue to their risks for persistent depression and suicidal ideation," said study senior author Adam Spira, a professor of mental health at Johns Hopkins in Baltimore.
"We can't say that the sleep disturbances we're seeing are necessarily causing the poor depression outcomes," he said in a Hopkins news release. "But the results suggest that older adults who are being treated for depression and whose sleep problems are persistent or worsening need further clinical attention."
Spira said the findings also suggest that treatment of sleep problems should be explored as a way to improve depression symptoms in older adults, as well as poor mental and health outcomes related to disturbed sleep.
The U.S. National Institute of Mental Health has more on depression.