By Anne Harding
NEW YORK—Treating depression in patients with comorbid insomnia is associated with improved insomnia symptoms, new research shows.
At the same time, though, people with worse insomnia at baseline appear to be less likely to see their depression remit with treatment, researchers report in the Journal of Affective Diseases, online August 30.
"Insomnia frequently can be seen before someone becomes clinically depressed and frequently exists once someone's clinical depression is in remission," Dr. Brittany L. Mason of the University of Texas Southwestern Medical Center in Dallas, the new study's first author, told Reuters Health by email.
"That leads us to believe that we may be seeing two disorders at the same time, instead of interpreting insomnia as a symptom of depression exclusively," she added. "This is a different way of thinking about this comorbidity than many clinicians currently think about it."
Almost 90% of people with major depressive disorder (MDD) have sleep problems, but lumping insomnia and hypersomnia together in one diagnostic domain "ignores distinct biological differences between those symptom presentations," Dr. Mason and her team note.
They compared insomnia symptoms in 2,788 adults with MDD and insomnia participating in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) trial.
The 16-item Quick Inventory of Depressive Symptomatology- clinician rated (QIDS-C) was administered several times throughout the study. The researchers created a global insomnia score ranging from 0 to 9 by adding the three insomnia-related symptoms from the QIDS-C (sleep-onset insomnia, mid-nocturnal insomnia, and early morning insomnia).
Repeated measures ANCOVA showed that insomnia significantly improved during the acute phase of treatment, from a mean 6.2 at baseline to 3.7 at week 9 of the study. At the end of the acute phase, which lasted for up to 14 weeks, mean insomnia scores increased to 4.4.
A one-point increase in baseline insomnia score was associated with a significantly reduced likelihood of depression remission (odds ratio, 0.88).
People with comorbid depression and insomnia often receive treatment for both conditions at once, Dr. Mason said.
"However, too frequently one or both is not being sufficiently treated so it is important that doctors ask, assess and treat when necessary," she said. "Plenty of medications are approved and used for the treatment of insomnia. However, the way we manage insomnia in the context of depression might require adjustments. This needs further study."
In future research, Dr. Mason said, "we hope to use more objective markers of sleep and sleep-related functioning, like activity measurement and electroencephalography (EEG) data in the context of assessing clinical depression and related symptom domains."
She concluded: "Assessing both symptoms of insomnia and of depression can help to provide a comprehensive assessment of patient needs and successful diagnosis and treatment of these conditions can improve patient health."
J Affect Disord 2019.
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