(RxWiki News) Methamphetamine users may not just be causing damage in the short term. They also are 76 percent more likely to develop Parkinson's disease as they age.
In addition to meth abusers, those who use other amphetamine-like stimulants also are at an increased risk for developing the neurodegenerative disease.
"Avoid using methamphetamines."
Dr. Russell Callaghan, lead researcher and a scientist with the Centre for Addiction and Mental Health, said the research provides evidence for the first time, though the connection has been suspected for about 30 years. Establishing the link has been challenging because Parkinson's tends to develop in middle and old age, and it was necessary to track a larger number of meth users over a long period of time.
Since Parkinson's disease is caused by an inability to make the neurotransmitter dopamine, scientists had suspected methamphetamine use could damage dopamine-producing areas of the brain. It had been shown in animals, and they suspected it might also be the case in humans.
During the course of the 16-year study, researchers examined California hospital records between 1990 and 2005. Use of the drug is prevalent in California.
Investigators reviewed records of 40,472 patients who were at least 30 years old and had been hospitalized due to methamphetamine or amphetamine use. Those patients were compared to two other groups including 207,831 admitted for appendicitis with no diagnosis of addiction, and 35,335 with cocaine use disorders.
The group of patients with appendicitis group served as a comparison to the general population. The cocaine group was used to determine whether the risk was specific to methamphetamine users since cocaine also affects dopamine. In addition, the cocaine users also served as a control group to account for health effects and lifestyle factors.
Parkinson's diagnoses were then identified from hospital records and death certificates. Only meth users had an increased risk of Parkinson's. The study is one of few to examine the long-term association between meth and the development of a major brain disorder.
Dr. Callaghan noted that methamphetamine is the second most widely used illicit drug in the world, and that the research will help doctors anticipate the full long-term medical consequences of such problematic drug use.