How does the drug affect the user?

The drug stimulates the central nervous system, with effects lasting anywhere from four to 24 hours. After using the drug for a long time, it changes the brain in long lasting ways, according to Dr. Alfred Heller of the University of Chicago. It destroys the endings of dopamine-containing neurons, resulting in a loss of this brain chemical. The nerves it affects are the same as those that are lost in Parkinson's disease. Meth can cause heart failure, brain damage and stroke.