- Children who had attention-deficit hyperactivity disorder (ADHD) were more than twice as likely to develop early-onset Parkinson's and other related motor diseases compared to non-ADHD individuals
- The estimated risk was six to eight times higher for ADHD patients prescribed stimulant medications, including mixed amphetamine salts, methylphenidate, and dexmethylphenidate
- Further studies need to be done to ascertain if the increased risk is due to having ADHD itself or perhaps a more severe form of ADHD, which is more likely to be treated with medications
Attention-deficit hyperactivity disorder (ADHD) patients have an increased risk of developing Parkinson's and Parkinson-like diseases compared to people with no history of ADHD, according to researchers at the University of Utah Health. The results are available in the journal Neuropsychopharmacology.
About 11 percent of U.S children, aged 4 to 17 are diagnosed with ADHD. However, what effect ADHD or the common medications used for its treatment would have on the long-term health of the children has remained understudied.
ADHD is a brain development disorder characterized by hyperactivity, inattention, disorganization, and impulsivity and is associated with changes in the release of a brain hormone, dopamine.
"Parkinson's disease is commonly thought of as a neurodegenerative disease associated with aging," said Glen Hanson, D.D.S., Ph.D., professor of Pharmacology and Toxicology and School of Dentistry at U of U Health and senior author on the paper. "This may be the first time where a childhood disease and its treatment may be linked to a geriatric expression of the neurodegenerative disorder."
The current study builds on earlier research that amphetamine abuse and the onset of Parkinson's disease could be related.
StudyThe non-ADHD individuals were chosen from the Utah Population Database (UPDB), which contains vital and medical records of more than 11 million individuals who have lived in the state. They examined twenty years of historical records and chose 158,790 eligible patients born between 1950 and 1992 with no prior diagnosis of Parkinson's or Parkinson-like diseases, who were residents of Utah after January 1, 1996, and at least 20-years old by the end of 2011.
The ADHD population was compiled based on UPDB, matching the groups on gender and age. The ADHD patients were 31,769 in number, of which 4,960 were prescribed stimulant medications. To be precise, 2,716 received amphetamine salts, 1,941 received methylphenidate, and 303 received both.
Hanson's team found that -
- The risk of ADHD patients developing early onset (21-66 years old) Parkinson's and Parkinson-like diseases was twice that of non-ADHD individuals of the same gender and age
- ADHD patients prescribed with methylphenidate, mixed amphetamine salts and dexmethylphenidate, all considered stimulant medications, had an estimated risk of six to eight-times higher
The study accounted for differences in gender and age and excluded people with a history of alcohol or drug abuse. It also controlled for factors associated with Parkinson's independent of ADHD like the effects of psychotic disorders and tobacco use. However, some of the factors that could contribute to the development of Parkinson's disease could not be excluded including head trauma, brain injuries, and environmental toxins.
The study had a few limitations - the non-ADHD subjects could have been diagnosed with Parkinson's outside of Utah, there could have been missed, or incorrect diagnosis of Parkinson-like disease symptoms and the study had insufficient information on the duration of use and dosage of ADHD medication prescribed.
Since the study results should be considered preliminary Hanson said, "I believe the treatment is still a benefit, especially for children who cannot control their ADHD symptoms. Medication really should be considered on a case-by-case basis."
- ADHD may increase risk of Parkinson's disease and similar disorders - (http://parkinsoncenter.org/feed-items/adhd-may-increase-risk-of-parkinsons-disease-and-similar-disorders/)