April 13, 2005
Rochester, Minn. — Parkinson's disease is a relatively rare disorder. It attacks neurons in the brain controlling muscle movement. Those who suffer from Parkinson's have trouble walking and often constantly shake. For the past 10 years, Mayo neurologist James Bower has been studying the disease. Bower says he's been looking for links between certain personality types and Parkinson's.
"There have been studies in the past that have suggested that a less adventurous, less novelty seeking personality as well as certain psychiatric conditions especially anxiety and depression, that both of these might be linked to the later development of Parkinson's disease," Bower explains.
Mayo researchers led by Bower looked deeper for a possible link. They tracked down a group of about 4,000 who took a popular personality test back in the 1960s. Researchers then determined that just over a hundred developed Parkinson's. Among those who did, a majority had received high scores for anxiety and pessimism. After crunching the numbers, Bower says it became apparent that those suffering from extreme anxiety might have as much as a 60-percent greater chance of developing the disease.
"We did find this association but now we need to figure out what it means," says Bower. "One explanation is that anxiety is actually a cause for Parkinson's disease. But there's also an alternative explanation and that it's not anxiety actually causing the illness but that maybe there's another risk factor like a gene that leads to both anxiety and Parkinson's later on. So we have to differentiate the two."
Bower stresses that extreme anxiety is much more intense than normal worrying. And he says more research needs to be conducted to determine if anti-anxiety medication could make a difference when it comes to the likelihood of developing Parkinson's.
In another study researchers determined that women who have both ovaries removed double their chances of developing Parkinson's. The loss of natural estrogen seems to be responsible. Bower says there's a similar link between the hormone and osteoporosis.
"What this study does is it tells us that not does natural estrogen seem to help the bones it also seems to help the brain in terms of Parkinson's disease," says Bower.
He says in many instances women have their ovaries removed as the result of some sort of medical emergency. But Bower says in cases where removal can safely be avoided it might a wise alternative to consider.
"They're getting a hysterectomy for some other reason and the discussion with the surgeon is while I'm doing your hysterectomy and taking out your uterus, should I also take out your ovaries? And then if you don't have ovarian cancer, it would be a less significant indication and that where there's more of a play of discussing the risk benefit ratio," he explains.
Bower expects research will continue. He says the findings should be especially useful to other scientists who share a determination to untangle Parkinson's many remaining mysteries.