Environmental and occupational risk factors for progressive supranuclear palsy: Case-control study.
"We did not find evidence for a specific causative chemical exposure; higher number of years of drinking well water is a risk factor for PSP. This result remained significant after adjusting for income, smoking, education and occupational exposures. This is the first case-control study to demonstrate PSP is associated with environmental factors." © 2016 International Parkinson and Movement Disorder Society
Finding a cause may help in finding the cure.