Methamphetamine Addiction Mechanism

Methamphetamine is a highly abused synthetic drug in the United States with a highly addictive quality. To understand how the toxin affects the body, researchers at Center for Human Development and Disability of University of Washington gave doses of meth to mice for 10 days, a period equivalent to chronic use in humans.

Long usage and withdrawal of the dosage degrades the neuronal terminals between the cortex and the striatum. Long periods of abstinence from meth does not revert the degraded terminals back to their original configuration; however, another intake of meth reversed these changes. The drug not only alternates several pathways in the brain but the only way of going back to the original configuration is by taking another dosage of the drug.

These pre-synaptic terminals affected by the drug allow for the flow of information between the cortex and the striatum. Basically, when a person sees something new, dopamine is released and it travels from the cortex to the striatum. When that person sees the same object again, since it is no longer new and curious, a lower amount of dopamine is transmitted. Meth results in an extremely high release of dopamine at once causing the drug consumer to remain focused on a certain object or goal for long periods of time. In a chronic user, the filtering mechanisms for dopamine are defeated and the only way to reignite the terminals to keep the flow of dopamine going is re-administration of the drug. Unfortunately, this implies that one cannot simply quit meth once addicted but can only hope to taper off eventually hoping that the brain damage is not already too severe.

http://www.sciencedaily.com/releases/2008/04/080409120619.htm