Asked by: Mary Smith, London
During rapid eye movement (REM) sleep, our body is paralysed to stop us from acting out our dreams. When sleep paralysis occurs, features of REM sleep are continuing into our waking lives. In particular we are unable to move and sometimes experience hallucinations.
Both genetic and environmental factors are at play. Circadian genes might be important, although more research is needed to specify which genes are involved. As for environmental influences, it appears that anything that might disrupt our sleep – including stressful life events and alcohol use – can be a risk for sleep paralysis.