Methamphetamine’s Effects on the Brain
Misuse of methamphetamine causes significant changes in the brain.
Neuroimaging studies have demonstrated alterations in the activity of the dopamine system that are associated with reduced motor speed and impaired verbal learning. Studies in chronic methamphetamine users have also revealed severe structural and functional changes in areas of the brain associated with emotion and memory, which may account for many of the emotional and cognitive problems observed in these individuals.
Research in primate models has found that methamphetamine alters brain structures involved in decision-making and impairs the ability to suppress habitual behaviors that have become useless or counterproductive. The two effects were correlated, suggesting that the structural change underlies the decline in mental flexibility. These changes in brain structure and function could explain why methamphetamine addiction is so hard to treat and has a significant chance of relapse early in treatment.
Some of the neurobiological effects of chronic methamphetamine misuse appear to be, at least, partially reversible. One study found that while biochemical markers for nerve damage and viability persist in the brain through 6 months of abstinence from methamphetamine, those markers return to normal after a year or more without taking the drug. Another neuroimaging study showed neuronal recovery in some brain regions following prolonged abstinence (14 but not 6 months). This recovery was associated with improved performance on motor and verbal memory tests. Function in other brain regions did not recover even after 14 months of abstinence, indicating that some methamphetamine-induced changes are very long-lasting.
Methamphetamine use can also increase one’s risk of stroke, which can cause irreversible damage to the brain. A recent study showed higher incidence of Parkinson’s disease among past users of methamphetamine.