Rare but relevant: Methamphetamine and Parkinson's disease.

Evidence from a number of paradigms suggests that methamphetamine use is associated with increased risk for the development of Parkinson's disease and parkinsonism, and that it may be associated with the premature development of Parkinson's disease. Prevalence of Parkinson's disease and parkinsonism is greater in both methamphetamine users and people who previously used methamphetamine, and evidence from animal studies provides a plausible mechanism for this observation. Despite this increased risk, Parkinson's disease is rarely diagnosed in methamphetamine users. Reasons for this may include under-detection, premature mortality, and individual and substance use characteristics which moderate the risk, including higher rates of smoking. Clinicians should be vigilant to signs and symptoms of Parkinson's disease and parkinsonism in methamphetamine users.