If you are used to taking commonly prescribed antidepressants think twice. According to a study you may be at high risk of developing dementia even 20 years before the actual diagnosis a study has warned. The researchers found greater incidence of dementia among patients prescribed anticholinergic antidepressants anticholinergic bladder medications as well as anticholinergic Parkinson's disease medications than among older adults who were not prescribed these drugs. Anticholinergics medications that block acetylcholine a nervous system neurotransmitter have previously been implicated as a potential cause of cognitive impairment said Noll Campbell assistant professor at the Purdue University in Indiana. However the