ADHD May Cause Increased Risk of Parkinson's Disease

An early form of Parkinson's disease may be more likely to develop in people with ADHD.

A team of researchers at the University of Utah studied the link between these two conditions. Posted in Nature Neuropsychopharmacology On Wednesday, the study found that the link was even more pronounced in patients treated with certain medications, such as amphetamines and psychostimulants such as Ritalin.

"In people who have been diagnosed with ADHD and have not been treated with a stimulant, there was about two-and-a-half times more likely that they develop disorders related to Parkinson's disease or Parkinson's, "Dr. Glen Hanson, professor of pharmacology and the vice-dean of the School of Dentistry at the University of Utah, who led Newsweek. "If they were treated with Ritalin or other amphetamines, this increase went from 2.4 to 8.6 times. There was this dramatic jump in the likelihood that they would develop a disorder similar to Parkinson's disease. "

Parkinson's disease is a neurodegenerative disorder whose symptoms include stiffness, tremors and difficulty walking, and cognitive problems in later stages of the disease, according to the Centers for Disease Control and Prevention. Scientists have not determined the exact causes of Parkinson's disease but believe it could be a combination of genetic and environmental factors. In the United States, approximately 50,000 people are diagnosed each year.

In this study, scientists analyzed 200,000 people with Parkinson's disease who were residents of Utah born between 1950 and 1992. Of the 200,000 people, about 32,000 were diagnosed with ADHD. The researchers checked their results for other factors that may influence the development of Parkinson's disease. For example, people with schizophrenia are more likely to develop the disease and people who smoke are less likely to develop the disease. These extremes were excluded.

Young children dance with their umbrellas at the launch of an art installation called Umbrella Project, which aimed to raise children's awareness of ADHD and autism. People with ADHD are more than twice as likely to develop Parkinson's disease. CHRISTOPHER FURLONG / GETTY IMAGES

A recent study found that the prevalence of ADHD among American children increased from 6.1% in 1997 to 10.2% in 2016. At the time when children in Hanson's study were children, the prevalence was even lower than in 1997. has also increased.

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"The use of psychostimulants was about 15 percent," said Hanson of his study population. "In today's world, they use psychostimulants to treat, I would say, half or two-thirds of these patients, so our population has far fewer patients treated with Ritalin than Ritalin now.

These changes could mean that, in the future, more people will be diagnosed with Parkinson's than they are today. Hanson said: "It's like the canary in the coal mine, we see the early stages that we can start asking the questions of Parkinson's disease, but we're not really where the majority of Parkinson's appears and it is after the age of 60 years. "