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February 11, 2009 6:21 PM
By Christine Lagorio
(WebMD) Attacked by snakes in his dream, a man strangles his sheets. Another, fighting dream intruders, punches his bedpost and breaks his arm. Others injure not themselves but their bed partners.
All of these people suffered an unusual sleep disorder in which they act out violent dreams. It’s called REM-sleep behavior disorder, or RBD. Most people who suffer RBD are men and most are over 50 years old.
But some people get RBD at a much younger age. What makes them different from people without RBD? A Mayo Clinic research team including R. Robert Auger, M.D., took a close look at 22 young RBD patients. They compared them with 22 age- and sex-matched people with a different sleep disorder, obstructive sleep apnea. They also compared them to older RBD patients.
“Eighty-percent of this early onset RBD group were using antidepressants vs. 15 percent of age- and gender- matched non-RBD controls,” Auger tells WebMD. “And we found antidepressant use was much higher in the younger group than in the older group of RBD patients.”
Auger reported the findings at this week’s annual meeting of the Associated Professional Sleep Societies’ SLEEP 2006 meeting in Salt Lake City.
Antidepressants Not Proven RBD Cause
What makes RBD different from sleepwalking is that it happens only during dreams. Dreams occur in the second half of the sleep cycle, during REM rapid eye movement sleep. Sleepwalkers, in contrast, aren’t dreaming, and usually begin their nocturnal activity soon after bedtime.
During normal REM sleep, the brain shuts down the body’s ability to move except for eye movement and the muscles needed for breathing. But this virtual paralysis doesn’t happen in people with RBD.
In fact, about half of people with late-onset RBD symptoms actually have Parkinson’s disease or a Parkinson’s-like movement disorder. Some two-thirds of people with true late-onset RBD, Auger says, eventually develop one of these degenerative brain diseases.
Recently, researchers have found that antidepressants affect REM sleep. So one explanation for the study findings is that in some people, antidepressants cause RBD. Auger is quick to point out that this isn’t the only explanation. People take antidepressants because they have psychiatric symptoms. This underlying illness could also be triggering RBD.
I don’t think it is something that would discourage me from prescribing antidepressants,” Auger says. “But doctors should be aware of this, because except for those in the sleep field, a doctor would not likely make the link between an unusual sleep disturbance and a medication.”
It’s also possible, Auger says, that somehow antidepressants are unmasking the same risk for Parkinson’s-like diseases as is seen in people who get RBD later in life.
These are “credible and important findings,” says Bruce Nolan, M.D., director of the sleep disorders center at the University of Miami Miller School of Medicine. But he worries that we’ll have to wait for definitive answers to the questions raised by the study.
“It is going to take a long time before many potential long-term effects of medications acting on the nervous system will be better understood,” Nolan tells WebMD. “The pharmaceutical companies are not likely to provide funding for such research.”
Neurologist Michael Yurcheshen, M.D., of the University of Rochester’s Strong Sleep Disorders Center, also praises the Auger team’s work.
“It is certainly an intriguing hypothesis,” Yurcheshen tells WebMD. “But at this stage it is really impossible to separate out whether it is the antidepressants, the underlying psychiatric condition, or some completely unexpected thing that is causing the sleep behavior.”
Don’t Stop Antidepressant Treatment
Auger says that in his experience, early-onset RBD goes away when patients switch to an antidepressant Wellbutrin that affects different brain pathways than most other antidepressants. This is by no means proven, however, as the number of treated patients is very small.
Yurcheshen agrees that overall, Wellbutrin has less of an effect on sleep than other antidepressants. Both he and Auger strongly advise people not to stop taking their antidepressant medications even if they suspect they have RBD.
“Anybody who has any symptom of RBD needs to see a sleep specialist to exclude neurological diseases, some of which are treatable,” Yurcheshen says. “And RBD, apart from other neurological conditions, can be serious all by itself. People have injured themselves; have injured their bed partners. They need a complete evaluation and treatment.”
Treatment for RBD begins with obvious things. First on the list: making sure patients and their bed partners are safe.
“You remove objects around the bed that might cause harm lamps, and things with sharp corners,” Yurcheshen says. “Sometimes you advise partners to sleep in different beds or bedrooms if they have been injured.”
Fortunately, most patients respond to a benzodiazepine drug called Klonopin. The few who do not respond to this drug often respond to high-dose melatonin.
Meanwhile, Auger says he will continue his systematic studies of RBD at Mayo Clinic.
SOURCES: Teman, P.T. Presentation to the Associated Professional Sleep Societies’ SLEEP 2006 meeting, Salt Lake City, June 17-22, 2006; Abstract 0797. R. Robert Auger, M.D., consultant, Mayo sleep disorder center; instructor in psychiatry and medicine, Mayo Clinic College of Medicine, Rochester, Minn. Bruce Nolan, M.D., director, Sleep Disorders Center, Miller School of Medicine, University of Miami, Fla. Michael Yurcheshen, M.D., consultant, Strong Hospital Sleep Disorders Center; assistant professor of neurology, University of Rochester, N.Y.