Dear Jason, Although it is true that substance abuse can be one of the causes of PD and that maybe some of the reason that we are seeing more middle aged people on the list I am offended to think that this is a major cause. As a middle aged PD person I did not do drugs in the 60's and am offended to be linked to an assumption of that kind. I tend more to believe more that the medical field is becoming far better at identifing problems sooner and therefore people with a disease are being identified at earlier stages in their life rather than latter. Thank you for letting me voice my opinion on those who would tend to lump things together and not consider sometimes that the options of other events and situations could also be a factor. Dar Newman