REM sleep is the stage of sleep when we have our most vivid dreams. Our bodies were ingeniously designed to have “atonia,” or complete lack of muscle tone, during REM except for the eye muscles and the diaphragm, the muscle that controls breathing. This prevents us from acting out our dreams. When muscles stay inappropriately “on-line” in REM, we call it REM Sleep Behavior Disorder, or RBD for short.
RBD is associated with a number of neurodegenerative conditions, most commonly Parkinson’s disease and related disorders that are caused by the accumulation of an abnormal protein called alpha-synuclein in the brain.
alpha-synuclein deposits in the brain
RBD is also associated with Alzheimer’s disease and other forms of dementia. The onset of RBD is highly predictive of developing one of these conditions, which may occur years or even decades later. One study showed that 80-90% of patients with RBD eventually developed a neurodegenerative condition. There is a strong male predominance to RBD with a reported male to female ratio as high as 9:1. It is important to make the appropriate diagnosis so that patients can be monitored closely for signs and symptoms of such neurodegenerative conditions. Unfortunately, at present time, there are no proven interventions to prevent such conditions.
In many cases, patients with RBD aren’t initially aware of the problem. Quite often it is the patient’s bedpartner who is initially bothered by the “dream-enactment.” Symptoms may include loud talking, crying out, screaming, flailing, punching or kicking. For reasons that are not yet understood, dreams typically involve being attacked or threatened, or having to defend oneself. Patients may be aware of having vivid dreams and waking themselves up crying out or striking with their limbs. Episodes are more common in the second half of the sleep period, when we have more and deeper REM sleep.
Punches and kicks may injure bedpartners who are often hesitant to tell medical professionals about these incidents, lest their bedpartner be accused of abuse. As the disorder progresses, dream-enactment behavior may evolve to falling out of bed and self-injury.
“Idiopathic” refers to cases where RBD arises spontaneously. “Secondary” RBD means the symptoms of RBD are a result of another primary condition. Secondary RBD is commonly attributable as a side effect of antidepressants. The other major cause of secondary RBD is an underlying primary sleep disorder that fragments REM sleep; most frequently this is obstructive sleep apnea.
Patients with PTSD may exhibit a variation of this disorder called “pseudo-RBD,” in which the patient re-experiences traumatic incidents during dreams. This particular disorder may respond to a medication called Prazosin, which calms the overexcited nervous system down.
The definitive diagnosis of RBD requires a sleep study showing evidence of REM sleep without atonia, in conjunction with a history consistent with the disorder. In practice, many clinicians elect to treat without a sleep study when they have a strong clinical suspicion for RBD.
It is important to mitigate factors that could be contributing to secondary RBD. Reducing the antidepressant to the lowest effective dose is helpful. If possible, switching an offending antidepressant to an antidepressant that doesn’t cause RBD, such as Wellbutrin, may be helpful. Treatment of obstructive sleep apnea, if present on the sleep study, is recommended.
It is important to assess the bed and bedroom and remove items that might injure the patient during dream enactment, such as sharp corners on nightstands and bed frames or easily breakable items, such as lamps. Firearms should be made inaccessible. In more advanced stages of the disorder, it may be advisable to install heavy drapery or other window treatments to prevent the possibility of injury from broken glass. Many patients find using padded bed rails or sleeping in a sleeping bag to be helpful.
Klonopin (clonazepam) is a mainstay of treatment. It is in the “benzodiazepine” class of medications which have anti-anxiety and muscle relaxant properties. Generally this is started at 0.5-1 mg at bedtime and titrated upward as needed to control symptoms. Potential problems with Klonopin include worsening coexisting sleep apnea by reducing muscle tone in the upper airway, impairment of memory function and balance, tolerance and dependence. A severe, life-threatening withdrawal syndrome may occur with abrupt discontinuation of this medication.
Melatonin is the other typical medication used for RBD. Generally it is started at 3 mg and increased as needed to a maximum of 10 mg or so. Melatonin is available as an over-the-counter sleep aid supplement. Its side-effect profile is generally mild and includes sedation. Since melatonin is classified as a supplement, it is not regulated by the FDA. Therefore, concentrations of melatonin may vary by brand. For example, it is possible that a melatonin supplement labeled as 3 mg may contain 2 mg of melatonin or even 0 mg of melatonin. Therefore, it is important to select a melatonin supplement that is certified by an appropriate verification agency such as USP.
Joseph Krainin, M.D., FAASM is the founder of Singular Sleep, the world's first online sleep center. He is board certified in sleep medicine and neurology and has been practicing medicine for over 11 years.
© 2020 American Sleep Association.