About a year <a href="http://ghettotube.in.net/" rel="nofollow">gettotube</a>  Yang pointed out to CBSNews.com that the study showed two groups in particular appeared to be at higher risk for Parkinson's: elderly people over 65 with depression, and people with difficult-to-treat-depression, who were defined as having to alter their antidepressant treatment regimen two or more times.