Researchers in Spain havemade a huge breakthrough after discovering another major link between the development of Parkinson's disease and complications relating to REM sleep behaviour disorder. Scientists at the Barcelona University Hospital found that patients with an REM sleep disorder were understood to have lower levels of dopamine in the brain, which progressively reduced over time. This meant that those suffering from nightmares - particularly ones where they are pursued - are more at risk of developing disorders like Parkinson's disease because of this lack of dopamine in the brain when they are asleep. The findings were published in the Lancet Neurology journal and follow a previous study back in 2006 where it was suggested that 45 per cent of patients with a sleep disorder go on to develop Parkinson's or another neurodegenerative disease, again linked to declining dopamine levels. However, it is not all negative news for Parkinson's sufferers. Recent research in the journal Neurology suggested that doses of ibuprofen reduce the risk of developing Parkinson's disease by around one-third.