Alcoholism can destroy a liver. Heroin needles can spread HIV. And cocaine can stop a beating heart. But addiction finds its home in the brain.
“Every drug of abuse has its own receptors that it acts on,” said addiction specialist Dr. Joseph Beck, head of the addiction program at Ingalls Memorial Hospital in Harvey.
“What they all have in common is stimulation of the ventral tegmental, which stimulates dopamine. That’s what links drug use to reinforcement.”
The National Institute on Drug Abuse explains that brains are wired to ensure people repeat activities, such as eating, by associating the activity with pleasure or reward.
“Whenever this reward circuit is activated, the brain notes that something important is happening that needs to be remembered and teaches us to do it again and again, without thinking about it,” according to the institute. “Because drugs of abuse stimulate the same circuit, we learn to abuse drugs in the same way.”
Drugs hijack the reward circuit, flooding the system with dopamine, which causes a high, according to the institute.
“Some people take drugs and hate it and never do it again,” Beck said.
Most people would be turned off by the agitation, sweating and “bugged-eyed” effects of cocaine, he said.
But trying a drug multiple times can lead to disruption. The hedonic tone — that is, the level of pleasure from doing something — throws dopamines out of balance, he said.
In a young person’s brain, the damage can be irreversible.
“When it’s done, it’s done … to an extent,” Beck said. “It might get better, but there is some significant difference. Drugs, if you’re a child, can modulate brain growth.”