Sleep and Depression
|Roseanne Armitage, Ph.D.|
Some people have more trouble adjusting to time changes than others, according to Roseanne Armitage, Ph.D., a U-M professor of psychiatry who directs the Sleep and Chronophysiology Laboratory at the U-M Depression Center. Armitage studies the connection between sleep and circadian rhythm disturbances and psychiatric illness.
Her research indicates that people with depression or bipolar disorder have circadian rhythm disturbances similar to those seen in people suffering from jet lag or lack of sleep. Depressed patients also are more vulnerable to jet lag and sleep deprivation, because it’s much more difficult for them to reset their circadian clock. So for people at risk for depression, maintaining a regular sleep cycle is especially important.
Armitage’s research suggests that disturbances in sleep and circadian rhythms can be a precursor to, not just a result of, depression. So treating depression alone without addressing the underlying sleep problem is not enough, because the depression is likely to return.
“It doesn’t mean that everybody who has circadian rhythm abnormalities or sleep disturbances will go on to develop depression or substance abuse, but the risk is significantly higher,” Armitage explains.
Armitage’s research shows that the link between abnormal circadian rhythms and depression can show up at an alarmingly early age. One of her studies involves 7- and 8-year-old girls who have been diagnosed with depression. Using actigraphs — watches that measure motion and record light levels every 60 seconds — Armitage tracked each girl’s pattern of activity for 21 days.
“If you look at how your day is organized, you switch tasks or take a rest about every 90 minutes,” Armitage explains. “This 90-minute rhythm persists throughout the sleep period in the REM/non-REM sleep cycle. One of the things we noticed in these young depressed girls is that the strength or amplitude of their rhythm was half what it is in healthy girls,” she says.
In another study, Armitage is testing a behavioral intervention approach to strengthen circadian rhythms and see if this can improve or prevent depression. Her research subjects are children who have been diagnosed with depression or have a high risk of developing the disease, because they have a parent with depression.
Children in the program follow a strict schedule with regular periods of activity and light exposure at appropriate times during the day. They wake up, eat, exercise and go to bed at the same time every day, even on weekends. After just eight weeks on the program, the children showed tremendous improvement in the strength of their circadian rhythms, according to Armitage.
“One of the things we want families to recognize is that if you have kids at high-risk for depression, the last thing you want to do is keep an erratic sleep/wake schedule,” she says. “No staying up late and sleeping until noon on the weekend, and then getting up at 6 a.m. on Monday.”
That advice about maintaining a regular sleep cycle goes for adults, too, Armitage adds. “If you are at risk for depression, cheating a little sleep-wise packs a bigger wallop then it does for a healthy individual.”
From Medicine at Michigan Vol 9, Number 1, Spring 2007