Our crazy dreams could be the result of one too many viewings of Inception—or they could be the precursor to a life-threatening neurodegenerative disorder. 

  Wired reports that men who suffer from REM sleep behavior disorder (RBD) "experience a sudden change in the nature of dreams." Dreams become more vivid and more violent, and instead of experiencing usual REM muscle paralysis, the dreamer is free "to act out the dream's punches, twists, and yells" (often to the danger of their bedmates). Researchers have discovered that men who are diagnosed with RBD are almost always eventually diagnosed with a neurodegenerative disease like Parkinson's disease or Lewy body dementia. "The consensus among all RBD researchers is that it's not a matter of if, but when," one researcher said. But anywhere from 15 to 50 years can elapse between the diagnosis of RBD and the second disease—good news for doctors who say it's important to start treatment for neurodegenerative disease before severe brain damage has occurred. "In the neurodegenerative realm, we just don't know any other clinical manifestations that can start so far in advance," one doctor says. "There are so few other illnesses that can have a window of decades from one clinical manifestation to another."