Why is parkinsonism not a feature of human methamphetamine users?
Moszczynska A, Fitzmaurice P, Ang L, Kalasinsky KS,
Schmunk GA, Peretti FJ, Aiken SS, Wickham DJ, Kish SJ.
Human Neurochemical Pathology Laboratory,
Centre for Addiction and Mental Health,
250 College Street, Toronto,
Ontario M5T 1R8, Canada.
Brain. 2004 Feb;127(Pt 2):363-70


For more than 50 years, methamphetamine has been a widely used stimulant drug taken to maintain wakefulness and performance and, in high doses, to cause intense euphoria. Animal studies show that methamphetamine can cause short-term and even persistent depletion of brain levels of the neurotransmitter dopamine. However, the clinical features of Parkinson's disease, a dopamine deficiency disorder of the brain, do not appear to be characteristic of human methamphetamine users. We compared dopamine levels in autopsied brain tissue of chronic methamphetamine users with those in patients with Parkinson's disease and in a control group. Mean dopamine levels in the methamphetamine users were reduced more in the caudate (-61%) than in the putamen (-50%), a pattern opposite to that of Parkinson's disease. Some methamphetamine users had severely decreased dopamine levels, within the parkinsonian range, in the caudate (up to 97% dopamine loss) but not in the putamen. As the putamen and caudate subserve aspects of motor and cognitive function, respectively, our data suggest that methamphetamine users are not parkinsonian because dopamine levels are not sufficiently decreased in the motor component of the striatum. However, the near-total reduction in the caudate could explain reports of cognitive disturbances, sometimes disabling, in some drug users, and suggests that treatment with dopamine substitution medication (e.g. levodopa) during drug rehabilitation might be helpful.
Methamphetamine psychosis
The methamphetamine epidemic
Methamphetamine and memantine
Methamphetamine v MDMA toxicity
Amphetamine withdrawal/depression
Methamphetamine and dopamine transporters
Methamphetamine: a Weapon of Mass Destruction?
Methamphetamine : sensitization and desensitization
Methamphetamine and dopamine/serotonin-releasing agents

and further reading

Future Opioids
BLTC Research
Utopian Surgery?
The Good Drug Guide
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World