Methamphetamine is toxic to dopaminergic and seratonergic neurons in rodents, but there is little data on the toxic effects of methamphetamine on the human brain. In rhesus monkeys, the neurotoxic effects of methamphetamine persist for four years.
Clinical observations suggest that methamphetamine may cause long-lasting injury to the brain. Some psychiatric conditions, such as paranoid psychosis may occur not only acutely during methamphetamine exposure but may persist for months or even years after cessation of methamphetamine use. PET studies demonstrate decreased dopamine transporters in abstinent methamphetamine users, which suggest long-lasting neurotoxicity. It is unclear whether the decreased dopamine transporter density represents down regulation, occupied transporters, or persistent loss due to neuronal damage.
In vitro evidence also indicates long-term neurotoxicity. Decreased concentration of the neuronal marker N-acetylaspartate (NA) is associated with neuronal damage. Diseases associated with decreased NA include dementia, epilepsy, MS, brain tumors, and cerebral infarction. Decreased NA has been demonstrated in the frontal lobe and basal ganglia of abstinent methamphetamine users. Other metabolite markers are also abnormal in methamphetamine users. Whether these abnormalities are reversible with treatment or longer periods of abstinence is unknown.
Next week: How do you make methamphetamine?
As always, if there are any questions, call the MTPC.
I am interested in any questions that you would like answered in “Question of the Week.” Please e-mail me with any suggestions at donna.seger@Vanderbilt.edu
Donna Seger, M.D.
Medical Director, Middle Tennessee Poison Center