Your personality sometimes can offer clues to your physical health. More than 50 years of research have confirmed, in the main, that aggressive, competitive Type A people are more likely to have heart attacks than calmer, more patient, Type B counterparts. • Could there be a Type P?
Kelly Sullivan, a researcher in neuroepidemiology at USF's Morsani College of Medicine, says there is evidence of an intriguing link between personality and Parkinson's disease.
She and a USF team found that patients with the condition are more likely to be cautious and avoid risk taking. "They took fewer activity risks and had a greater preference for routine," said Sullivan, who cautioned that this is a fairly small study that needs to be tested further.
Researchers interviewed 89 people with Parkinson's and 99 who didn't have the disease. They were asked about their personalities in early adulthood and today.
Did they ride roller coasters, motorcycles, wear seat belts, gamble, or like to fly in small airplanes? Did they tend to plan out their days and stick to a schedule, including going to bed and rising at the same time throughout their lives?
"Those with Parkinson's had higher levels of harm avoidance, took fewer risks in their 20s and 30s and remained that way across their lives," said Sullivan, who presented the results last month at a meeting of the American Academy of Neurology.
None of which is to say, however, that you can protect yourself from Parkinson's by doing wild and crazy things. The study found an association; it didn't explain how it happens. But here's the theory:
People with Parkinson's have lower levels of a brain chemical called dopamine which is associated with muscle movement. Lower dopamine levels may also affect personality.
Dopamine gives us that rush of excitement, when driving at high speeds or riding a roller coaster. If you don't get that rush of pleasure, you're less likely to go in for risky activities.
But it isn't until dopamine gets very low, about 70 percent of normal or less, that the physical symptoms of Parkinson's appear, such as tremors, stiff posture, difficulty walking and others.
By the time these hallmarks develop, scientists believe the progressive disease has been under way often for decades.
So the USF research's value could be in aiding earlier detection, and some day, better treatment
"Our findings suggest that early life personality characteristics might be useful in identifying people at higher risk for Parkinson's," said Sullivan. "This study gives us insight into the preclinical characteristics of the disease."
Frank Sparrow, 59, was diagnosed with Parkinson's two years ago. He was in technical sales most of his life. "I was pretty organized, I had to be," said the Lake Alfred man, who since his diagnoses has been working part time in real estate.
"I had large customers, I sold communication services to universities and hospitals. To make a mistake with one of them would be a big deal. I characterize myself as pragmatic and organized," he said.
He's scratching his head over the new report.
"For the life of me I'm trying to figure out how they made that connection," said Sparrow. "I took calculated risks in business and in private life.''
Water-skiing, snow skiing, scuba diving, and zip lining above tree tops are all sports he's enjoyed.
"But jumping out of an airplane, I think is insane," he said.
Risk aversion is not the only personality trait linked with the condition. For instance, a 2010 report found a connection between anxiousness and Parkinson's.
Dr. Dean Sutherland, director of the Southeastern Center for Parkinson's Disease in Sarasota, said a possible connection with risk aversion has been talked about for years.
"But never has there been a study that's been as convincing as this one," he said.
Does Parkinson's cause those personality traits? Or do the personality traits cause something to go wrong biologically that leads to Parkinson's?
"We don't know," said Sullivan, "We need to do more research. Ours was a small sample and it wasn't conclusive."
Still, Sutherland, who treats patients with the condition, is intrigued at the possibilities. Personality tests might reveal the disease early, when it might be easier to stop.
"This kind of research could drive industry to find drugs and treatment that halt or slow the progress of the disease,'' he said. ''We don't have anything that does that right now.''