By Randy Dotinga
FRIDAY, June 12 (HealthDay News) -- New research sheds light on two of the mysteries of Parkinson's disease: the spike in creativity that some people develop and a personality type that is thought to be shared by many with the disease.
One new study reports that those who develop heightened creativity lose some of it when they go off certain drugs. And another study has found no link between the kinds of personalities people had in their younger years and their risk of developing Parkinson's.
The second finding is disappointing because it appears to mean that doctors won't have a potential tool to predict the disease, said Dr. Walter A. Rocca, a professor of epidemiology and neurology at the Mayo Clinic College of Medicine.
"There is this very interesting possibility that people at risk of Parkinson's disease could be recognizable many years before they develop the disease itself," Rocca said. "As far as we can tell, this does not seem to be true for personality traits."
Doctors who treat people with Parkinson's had thought differently for quite some time, he said. The assumption was that Parkinson's patients often "would be less willing to take risks or chances, a little bit more morally rigid," Rocca said. "They were into following the rules, very straight, introverted, punctual, conventional."
In their study, Rocca and his colleagues looked at the medical records of 6,842 people who took a test in the early 1960s that gauged their personalities. They then were followed for 40 years to see what happened to them.
Of the participants, 156 developed Parkinson's disease. But the researchers found no indication that people with specific personality types were more likely to develop the disease.
"The beauty of the study is that it's very historical," Rocca said. "You're really able to measure people when they had no clue" that they'd develop Parkinson's disease.
Yet despite the findings, he said, it's possible that personalities might have something to do with Parkinson's. "People can argue there are other ways of measuring personality, other personality traits we did not consider," he said.
It's also possible that personalities might change when people develop the disease, and families might think the changes began earlier, he said.
The findings are being released this week in Paris at the International Congress of Parkinson's Disease and Movement Disorders.
Also at the conference, French researchers are reporting that the drugs used to treat Parkinson's disease have varying effects on creativity.
The disease is thought to hurt creativity, although treatment with dopamine agonist therapy -- which reduces dopamine levels -- can boost it.
The study involved people who underwent deep-brain stimulation, a surgical treatment for Parkinson's disease that appears to help some people, although it's not entirely clear why.
Researchers found that those who had the treatment and underwent dopamine replacement therapy lost creativity if the therapy was too "drastically reduced."
The study is so small that "it's hard to extrapolate from this to the general Parkinson's population," said Dr. Hooman Azmi, director of movement disorders at Hackensack University Medical Center in New Jersey.
But, he said, the findings come from a "very well-respected" group of researchers. And previous studies have suggested that creativity is boosted as dopamine levels go up, he said.
By contrast, creativity dips in some people with Parkinson's.
"It doesn't just affect their movement," Azmi said. "It affects their whole brain function."
There's a potential problem, however. Dopamine can cause mania in some people and can lead to gambling addictions and other disorders, Azmi said.
The U.S. National Institute of Neurological Disorders and Stroke has more on Parkinson's disease.
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