REM sleep behaviour disorder: acting out dreams, causes, safety and treatment

During REM (rapid eye movement) sleep, when most vivid dreaming happens, the body is normally paralysed so that dreams are not physically acted out. Parkinson's UK explains that in people with Parkinson's changes in the brain may disrupt this process, so you may act out your dreams while you are asleep. This is called REM sleep behaviour disorder.

Royal Papworth Hospital describes the same condition as a combination of vivid dreams with aggressive content, associated with often violent physical movements related to the dream or nightmare, due to an abnormality in the formation of REM (dream) sleep. The characteristic feature is that the person feels they are being attacked or chased, or are attacking or chasing someone or something else, and responds aggressively, although in the early stages there may be only kicking movements with swearing.

Parkinson's UK lists what may happen while dreaming: kicking, speaking or shouting, punching, thrashing around in bed, falling out of bed and injuring yourself or your partner. You may not remember anything about it when you wake up, and many people are not aware that they have it.

People may see a GP, specialist or Parkinson's nurse because of realistic, vivid dreams, falling out of bed at night, waking with unexplained injuries or bruises from kicking, punching or bumping into things while acting out dreams, or very disrupted sleep. The NHS describes disturbed sleep, often with violent movements and shouting out, among the symptoms of dementia with Lewy bodies.

Because partners usually see the behaviour, a description from them is useful. A short video taken on a phone, with the sleeper's agreement, can help a clinician to distinguish RBD from other night-time events.

Royal Papworth Hospital says RBD is usually seen in males over the age of 50 but can be induced by drugs or alcohol in younger people, and that many people who develop it subsequently show features of Parkinson's disease. Parkinson's UK says it is thought to affect around half of people with Parkinson's and can also be an early sign of Parkinson's before motor symptoms develop.

The NHS lists disturbed sleep, often with violent movements and shouting out, as a symptom of dementia with Lewy bodies, which is another condition in which this sleep problem is recognised. These associations do not mean that everyone with RBD will develop one of those conditions, and not every person with Parkinson's has RBD, but it is a reason to ask for a neurological assessment and to report any new movement, memory or thinking changes.

Royal Papworth Hospital explains that many different events can happen during sleep and that it is important to pinpoint the type accurately. The type of movements, whether they link to dreams, how much the person remembers, the time of night and triggers such as sleep deprivation, alcohol or drugs all matter.

It contrasts RBD with sleepwalking, which is due to incomplete awakening from deep non-dream sleep, usually with only partial responsiveness and little recollection, and with nocturnal epilepsy, in which specific types of seizure occur at night and may be treated with anticonvulsant medicines. It notes that it may be necessary to come into hospital for polysomnography to see exactly what is going on.

Royal Papworth Hospital says the diagnosis can be confirmed by polysomnography, a sleep study in which sensors record brain activity, eye movements, muscle tone and movements during sleep. A GP will take a history, including medicines, alcohol and other symptoms, and may refer you to a sleep clinic or neurologist.

Royal Papworth Hospital notes that it can be induced by drugs or alcohol, so a clinician will want to know exactly what you take and drink. Do not stop any prescribed medicine without advice.

Parkinson's UK suggests changes to reduce the risk of hurting yourself at night. These include removing potentially dangerous items from the bedroom, adding protective padding to the corners of bedside tables, moving furniture with sharp edges away from the bed, placing pillows to stop you falling out of bed or striking the wall, and sleeping alone until symptoms are under control.

A Parkinson's nurse can help you work out what changes suit your circumstances. If you share a bed, discuss with your partner a plan for what to do if an episode occurs, such as not trying to restrain or forcibly wake the sleeper but speaking calmly from a safe distance; Royal Papworth Hospital advises that attempts to restrain or waken a sleepwalker should be avoided because it may lead to sudden violence.

Parkinson's UK says that a specialist may suggest sleep hygiene measures or medication, such as melatonin or clonazepam. Royal Papworth Hospital says that treatment with specific types of hypnotics is usually effective and that drugs such as melatonin and gabapentin may also be useful. These are specialist decisions, so ask your team about the benefits and side effects of each option.

Regular waking times and bedtimes, avoiding alcohol and other sedatives before sleep, and treating other sleep problems such as sleep apnoea are sensible supportive measures. If you take medicines for Parkinson's, ask your Parkinson's team whether timing or doses may be contributing.

Speak to your GP, specialist or Parkinson's nurse if you or your partner are worried about movements or behaviours during sleep, as Parkinson's UK advises. Seek urgent help if there has been a significant injury, a head injury or a fall, or if episodes come with confusion on waking, loss of consciousness or incontinence that could suggest seizures.