REM-sleep behaviour disorder


Patients with REM Sleep Behaviour Disorder (RBD) experience abnormal movements during REM (dream) sleep, such as 'acting out dreams'. This is a rare condition caused by abnormalities in the brain's behaviour when shifting between dream and non-dream states.

RBD is predominantly seen in older males, many of whom later develop neurodegenerative disorders (such as Parkinson’s disease, multiple system atrophy or dementia). RBD in the younger population, especially young female patients, is likely to be associated with medication, narcolepsy, or a structural central nervous system lesion.

When dreaming occurs during Rapid Eye Movement (REM) sleep in normal patients, the brain blocks signals from being sent to the muscles, in order to prevent us from acting out dreams. In patients with RBD, signals from the brain to muscles are not blocked during REM sleep, allowing the sufferer to act out dreams (which are often violent, horrific or frightening in nature).

Due to the unusual nature of the condition, RBD is often misdiagnosed as a disorder of arousal, a seizure or a limb movement disorder.

Causes of REM sleep behaviour disorder

Causes of acute (short-term) REM sleep behaviour disorder include withdrawal from alcohol and illicit substances, intoxication and the effect of other substances including caffeine and tri-cyclic anti-depressants.

Causes of chronic (long-term) REM sleep behaviour disorder include toxic-metabolic factors, brain tumours, infectious diseases, vascular problems (e.g., stroke), traumatic, developmental, congenital and genetic factors

Some patients are diagnosed with idiopathic RBD, which means that an identifiable cause for the condition could not be found.


RBD is usually diagnosed both clinically (based on reported symptoms and patient history) and with an overnight sleep study. Clinical symptoms of the condition include

  • Problem sleep behaviour that is harmful or potentially harmful
  • Behaviour disruptive to sleep
  • Behaviour annoying to patient or bed partner (includes violent behaviour).


In severe cases, REM sleep behaviour disorder can be treated with medication. Measures to prevent harm to self or others should always be taken (for example, removing sharp, glass or dangerous objects from the bedroom, proving extra padding with pillows etc). Measures such as the Pelican Floor Mat (click here for more link) are helpful to ensure patient safety.