Methamphetamine use and future risk for Parkinson's disease: Evidence and clinical implications.

BACKGROUND: Methamphetamine use has been posited to be a risk factor for the development of Parkinson's disease (PD) and parkinsonism. The clinical implications of a potential association between methamphetamine use and PD are considered.

METHODS: A review of methamphetamine and PD and parkinsonism was conducted, including evidence from animal models, clinical and population studies.

RESULTS: There is biological plausibility to a link between methamphetamine use and PD. Though clinical and epidemiological evidence in this area is scant, a number of studies suggest that methamphetamine is associated with a moderately increased risk of PD and parkinsonism, and may also lead to premature onset of PD. The long lag time between exposure to methamphetamine and onset of PD, the potential for recovery from neurotoxic effects, and tobacco smoking each may attenuate the association. Individual and drug use characteristics that may modulate a user's risk remain poorly understood.

CONCLUSIONS: The use of methamphetamine may be an initiating event in the development of PD and parkinsonism, in addition to other risk factors that a given individual may hold. Clinicians should be vigilant to signs of prodromal and emerging PD among methamphetamine users. In individuals with premature onset illness, information on current or prior exposure to methamphetamine should be sought.