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A Link Between Insomnia and Depression?

According to the National Institute of Mental Health, nearly seven percent of adults in the U.S. experienced at least one major depressive episode during 2012. Women, in particular, are twice as likely as men to experience depression. Therapy and antidepressant medications are common treatments for depression, but can treating insomnia be another route to combating the mood disorder?

People with insomnia are twice as likely to develop depression compared to those without insomnia. Chronic primary insomnia, which is defined as sleep problems not associated with other health conditions, may increase a person’s risk for depression later in life. So what makes a person with insomnia more susceptible to future depression?

Brain Size and Risk of Depression

Research by Dr. John Winkelman, within the Division of Sleep and Circadian Disorders at BWH, points to a possible answer: brain size.

Dr. Winkelman noted that the part of the brain that regulates mood (anterior cingulate cortex – ACC) was smaller among people with depression compared to those without depression. He found that those who experienced insomnia but not depression had larger ACCs than those with normal sleep. This led the researchers to hypothesize that larger ACCs could be a protective trait against developing depression.

“What we saw is that these insomniacs with larger ACCs never developed depression. These are people with risk, but were resilient to the disease.”

The researchers hope that the findings will eventually help clinicians better identify and treat people with insomnia who may go on to develop depression later in life.

“If we can intervene and treat their insomnia, then perhaps we could prevent them from developing depression later down the road,” said Dr. Winkelman.

People with insomnia are twice as likely to develop depression compared to those without insomnia.

Menopause, Depression and Sleep

For those already struggling with depression during the menopause transition, an effective intervention may lie in a better night’s sleep.

Hadine Joffe, MD, MSc, director of the Women’s Hormones and Aging Research Program in BWH’s Department of Psychiatry, is working to build a better understanding of the biological mechanisms behind depression in women.

In a study published in the Journal of Clinical Endocrinology and Metabolism, Dr. Joffe and her team detailed how hot flashes, hormones, and sleep affected women with menopause-associated depression. Seventy-two peri- and post-menopausal women experiencing depression, hot flashes, and sleep disturbance were randomized to receive estradiol (a hormone therapy to treat hot flashes and other menopause symptoms), zolpidem (a medication to treat insomnia) or placebo for eight weeks.

Dr. Joffe observed that for peri- and post-menopausal women, depression symptoms improved when their sleep quality improved, regardless of what treatment they were given.

“These particular results show that targeting insomnia in peri- and post-menopausal women may be critical in the overall management of depression,” said Dr. Joffe.

While targeting insomnia in women with menopause-associated depression is a key part of improving mood, Dr. Joffe noted that antidepressants and psychotherapy remain the primary treatment of depression for these women. However, as seen in other studies of depressed individuals, addressing sleep disruptions is important in managing depression symptoms and preventing its recurrence. 

In this video, Charles A. Czeisler, MD, PhD, Chief of the Division of Sleep and Circadian Disorders at BWH, explains the impact of sleep on brain function and physical health.