How to Get Great Sleep

For many of us, bedtime can be a torment. Ironically, when it comes to sleep, we're our own worst enemy. Our efforts to get some rest often turn one fitful night into full-blown insomnia.

By Hara Estroff Marano, published on November 01, 2003 - last reviewed on April 12, 2007

It also seems to be the true mother of depression. Most depressed people have trouble sleeping. But insomnia is not just a symptom: It's the single best predictor of depression, says Perlis. He has found that two or more weeks of sleeplessness increase the risk of a first episode of depression by 400 percent—even for someone who has never before been depressed. For those who have struggled with depression before, insomnia often heralds a recurrence.

Perlis contends that insomnia is actually "an unleashing factor" for depression. His longitudinal studies show that insomnia often precedes episodes of depression by about five weeks.

In depression, the architecture of sleep goes awry. Normally, during the course of the night, we gradually slip into deeper and deeper slumber. After hitting the deepest stage, we burst into dream sleep, marked by dramatic brain activity and rapid eye movement (REM). Normally, we cycle through these stages of sleep every 90 minutes or so.

But the depressed are on a fast track to dreamland. They dive too quickly into REM sleep, which lasts nearly twice as long as it does in the nondepressed. It's also a souped up version of the REM phase. It's more intense—parts of the brain that deal with emotions are more activated and the depressed sleeper tends to fidget much more.

It seems that at least one purpose of REM sleep is to promote the consolidation of memory, to reinforce what we learn during the day and integrate it into long-term memory—and to strip new memories of whatever emotional charge they initially carried. "You especially need REM sleep when you're depressed to process negative affect," explains Michael Thase, professor of psychiatry at the University of Pittsburgh Medical Center and Western Psychiatric Institute and Clinic.

But in the depressed, "there's so much water in the dam, it can't be contained," says Perlis. The central nervous system stays aroused. Mental hyperactivity, particularly intense in the amygdala and limbic cortex of the "emotional brain," leads to an increase in negative thoughts. The depressed become overly biased to remember bad things. And instead of helping to regulate mood, REM sleep in the depressed actually worsens it. The memory is "always as bad as it was the first time," says Perlis. One common problem in depression is awakening in the early morning. This may be the body's attempt to reduce negative affect by interrupting the last (and normally the longest) cycle of REM sleep.

Most intriguing, the evidence suggests that treating insomnia may forestall a first episode of depression, or a recurrence, and at least keep insomnia from becoming chronic. "It may be," says Perlis, "that if we get rid of the insomnia, we get rid of the depression risk." And that is one more reason not to panic the next time you find yourself wide awake at 3 a.m.