At JohnT's request here is some information about my identical twin who does not have PD and I. He wanted to know if he has any PD symptoms and how our lives differed. He suggested I start a thread.

My brother has taken the UPDRS and came out normal on everything.

Our lives were pretty much the same in terms of environment and behavior until early adulthood. He has been married to the same woman since the late 60's. I was divorced once and my second wife died of cancer in 2010, about the same time this malady made itself known. I also took care of our dying parents as he lives on the east coast and we live in California. All things considered his life has been more stress-free.

He went into the intelligence business with the government and I became a pharmacist. My presumption is that I have had more exposure to chemicals than he. In addition, I have taken handfuls of supplements since the '80's and he hasn't. I also used to experiment with brain machines such as sound and light, cranial electrostimulators, psychoacoustic tapes and CD's, etc. He didn't. He did meditation and spiritual practices more than I.

I traveled abroad and lived in Germany and Italy. He traveled but did not live overseas. I was probably more physically active with skiing, backpacking, etc.

My left foot was injured on several occasions. I was knocked unconscious by falling rocks in a canyon I was exploring. As far as I know he has not had any similar experiences.

We were both sick with infections as children fairy often starting when we were born prematurely and almost died. As I mentioned I kept a lot of birds but do not recall any unusual infections from them.

Currently he has prostate issues and arthritis, not uncommon at 64. I don't have those.

If I can think of any significant differences I have forgotten I will add it later.

I have thought for some time that the role of caregiver seems to itself turn up as a possible precursor to PD itself. My wife and I put in eight years caring for my grandparents and my PD was diagnosed just as that period came to a close.

The deep and chronic anguish that comes with longterm care for someone you love and for whom there is no hope can become a terrible thing. You are caught in an intensely painful trap from which there is no obvious escape. Your own health at some point begins to crumble.

If any psychology types (such as our benefactor Doc John) are looking on, it would be interesting to know their thoughts.

If you put a mouse in the situation of being subject to an electrical shock and being unable to escape, he enters a state of "learned helplessness" and simply gives up. He lays in the bottom of his cage as the shocks ravage his body. He has no hope.

What is our experience in the case of suffering the pain of extended suffering before which we are helpless? The cage from which we cannot escape? Or when the cage itself is so well repressed as to be invisible? When "Mommy" really was an angel but one that brought a price that would make Satan blush?

Remember that we have three core responses to threat - fight, flight, or freeze. It seems obvious to me that a number of us have chosen the latter because we could not bear to see Mommy's tears or Daddy's rage.

Does that explain PD? No, probably not. Is it irrelvent? Not for a minute....

Thanks for your story GerryW.

I'm not a twin, but picked on the fact that you had more stress in your life than your twin. I wonder if stress can trigger PD in a person, not cause it, but trigger it to emerge sooner rather than much later in ones life? Without getting into details, I had the most stressful year of my life just prior to my symptoms starting at age 58. Just a thought. I look forward to replys from other twins.