I popped the first pill and waited. After I had popped my fourth pill, I remember thinking that the truck was moving so slow. I thought I could get out and run faster than the truck. Carter was driving 70 mph. Methamphetamine triggers the release of dopamine, an excitatory nerve transmitter, and gives the person a feeling of euphoria.
Experts say an addict's brain is physically and chemically different from a normal brain.
A recent Newsweek feature on methamphetamine explains that cocaine, heroin, nicotine, amphetamines and other addictive drugs alter the brain's pleasure circuits. Activating this circuit produces a dopamine, a feel-good sensation, producing feelings from mild happiness to euphoria. When all the transporter molecules are occupied by cocaine or amphetamines, there is no room for dopamine, which therefore hangs around and keeps the pleasure circuit firing. This process is the vicious cycle of addiction. Soon, Carter was regularly using amphetamines and marijuana.