Dear Doctor: My husband, who has been diagnosed with a sleep disorder, acts out all his dreams. He recently tore his rotator cuff and dislocated his shoulder when he fell out of bed during a dream about playing basketball. We’re worried this might happen again. Are there any new treatments or research into this disorder?

Dear Reader: It sounds as though you’re describing what’s known as REM Sleep Behavior Disorder. This happens when an individual overcomes the natural paralysis that typically accompanies the dream state and literally engages in the physical activities of the dream.

We spend our time in two basic stages when we sleep. There’s REM (rapid eye movement) sleep, which is when we dream. And there’s non-REM sleep, which is made up of several different stages of deeper sleep. Throughout the night, we cycle through these different stages, with up to a quarter of the time spent in REM sleep, and the rest in the various stages of non-REM sleep.

During REM sleep, blood pressure goes up, breathing becomes uneven, the eyes dart back and forth, and the brain is extremely active. In normal REM sleep, a natural paralysis sets in, which ensures that our dreams remain in our minds and don’t cross into the physical realm. However, in REM Sleep Behavior Disorder, also known as RBD, that paralysis is either incomplete or not present at all. As a result, the sleeper takes an active part in those dreams.

The behaviors of RBD range from speaking, shouting and swearing in one’s sleep, to running, leaping, grabbing and punching. Patients report that their dreams are always active, and often violent. Although this time it was your husband who was hurt, those who share a bed with someone with RBD are also at risk of physical injury.

At this time, treatment consists of making the bedroom safer for the patient and his or her bed partner, and medications for the patient. Padding on, around and below the bed, lowering the bed itself, and de-cluttering and removing potentially dangerous objects is recommended. When it comes to medications, the anti-anxiety drug klonopin has been shown to be effective. Sometimes melatonin, a regulator of the sleep cycle, is prescribed as well.

Although the cause of REM Sleep Behavior Disorder is not yet known, studies have found a link between the disorder and the future onset of degenerative neurological conditions like Parkinson’s disease. According to the authors of the most recent study, published in the journal Neurology Today in September 2017, up to 75 percent of patients eventually develop Parkinson’s or a related condition. The thinking is that the symptoms of RBD indicate neurological changes that precede the symptoms of Parkinson’s and other similar disorders.

We realize this sounds alarming, which is why we urge you and your husband to get a second opinion at a recognized sleep center. Your husband will undergo a physical and neurological exam, he may be asked to undergo an overnight sleep study, and you may be interviewed for details about his sleep patterns. If the RBD diagnosis proves accurate, you will then be in good hands to deal with the disorder.

Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and primary care physician at UCLA Health.