Several Sleep Disorders Reflect Gender Differences

Poor sleep may increase women's vulnerability to mood disorders, according to speakers at a recent two-day workshop on women and sleep held in Washington, D.C.

Women of all ages are more apt than men to report trouble falling asleep, staying asleep, and waking too early or unrefreshed. Women are 1.4 times more likely to develop insomnia than men, according to a meta-analysis of 29 studies involving nearly 1.3 million adults published in Sleep in January 2006, said Christopher Drake, Ph.D., an assistant professor of psychiatry and behavioral neurosciences at Wayne State University School of Medicine. The gender differences in insomnia emerge at puberty and increase with age.

A primary symptom of depression, insomnia also may be an independent comorbid condition, said Drake, one of two dozen speakers at the workshop, which was co-sponsored by the National Sleep Foundation and the Atlanta School of Sleep Medicine. Specific treatment of insomnia may, however, improve sleep and ease depression, he noted. Sleep disturbance is the single most common refractory symptom in successfully treated depressed patients, and it increases the risk of relapse.

Women also have higher rates of chronic pain disorder than men do, a condition often comorbid with insomnia, Drake said. Behavioral treatment of pain-related sleep disturbance often benefits sleep and reduces pain.

Sleep laboratory studies reveal gender differences in sleep regulation in depressed women and men, said Roseanne Armitage, Ph.D., a professor of psychiatry and psychology and director of the Sleep and Chronophysiology Laboratory in the University of Michigan's Depression Center.

In depressed women, a small sleep challenge—delaying the onset of sleep by three hours—evokes an increase in slow-wave restorative sleep activity equivalent to that seen with total sleep deprivation in healthy women. It takes total sleep deprivation to evoke a response in depressed men.

Since the same brain mechanisms involved in sleep regulation are involved in mood regulation, Armitage said, this finding meshes with the phenomenology of depression. Depressed women tend to have more changeable or fluctuating mood, whereas depressed men tend to have flat, depressed mood.

Armitage's review of gender- and age-related sleep abnormalities in depression was published in the February Acta Psychiatrica Scandinavia.

Insomnia, depression, fatigue, and hypothyroidism are common but underrecognized presenting symptoms in women with obstructive sleep apnea (OSA), said Nancy Collop, M.D., an associate professor of medicine at the Johns Hopkins University School of Medicine and president of the American Board of Sleep Medicine. People with OSA may stop breathing dozens, even hundreds of times a night.

OSA historically has been viewed as a male disease, Collop said. The typical male patient snores loudly, is obese, and complains of daytime sleepiness. Failure to appreciate gender differences in OSA symptoms may prompt misdiagnoses of women and delay their referral to sleep specialists, she maintained. OSA, a risk factor for heart attacks and strokes, affects an estimated 4 percent of middle-aged men and 2 percent of middle-aged women.

Depression and anxiety are common complaints in people with restless legs syndrome (RLS), a disorder that affects women roughly twice as often as it affects men, said Barbara Phillips, M.D., a professor of medicine at the University of Kentucky's Chandler Medical Center and chair of the National Sleep Foundation's board. RLS often emerges during pregnancy and usually resolves promptly following delivery. It may reappear in subsequent pregnancies or later in life.

Symptoms of RLS worsen with inactivity and show a circadian pattern, peaking at night and disrupting sleep. RLS patients often report a diminished quality of life.

Selective serotonin reuptake inhibitors (SSRIs) used to treat depression may exacerbate RLS, Phillips cautioned. Older antihistamines in some over-the-counter sleep aids and antiemetic drugs also may have this effect.

About 85 percent of people with RLS experience periodic leg movements of sleep (PLMS), a disorder involving frequent repetitive leg jerks that cause transient partial arousals. While sleepers with PLMS often focus on their daytime fatigue, bed partners alert them to their nighttime behavior. Some antidepressants induce or worsen PLMS, too, Phillips said. Small studies suggest that bupropion may be less likely than SSRIs to worsen RLS and PLMS.

Dopamine agonists are first-line treatments for RLS. They are so effective in relieving RLS symptoms, she said, that lack of response to therapeutic doses should prompt reassessment of the diagnosis.

“Because sleep disturbance often is a marker of mood disturbance, and because both mood disturbances and the medications used to treat them may disrupt sleep,” said Phillips. “asking about sleep is an important part of ongoing psychiatric care.”

A conference summary is scheduled to be posted at<www.sleepfoundation.org>.▪