Addiction and the Brain

Scientists now know that addiction is the result of key changes in the brain.

For example, all drugs of abuse affect the dopamine pathway in the brain. Dopamine is a kind of neurotransmitter - a chemical produced by nerve cells that process and transmit information in the brain. The dopamine neurotransmitter's job is to produce feelings of pleasure so this pathway is commonly known as the "pleasure pathway."

"What happens when people develop a substance use disorder is that they tax the ability of their dopamine system to keep up," says Dr. Kathleen Brady, an addiction researcher at the Medical University of South Carolina. "The amount of dopamine we have in our brain is limited by the substances that the brain uses to make dopamine. And if we release it too often, we get into a situation where the brain has less dopamine. What that means is that an individual who has depleted their dopamine source in their brain has a difficult time feeling pleasure from even the normal events that would make someone happy - a mother seeing her child, or having a good meal."

The dopamine pathway is not the only part of the brain affected by addiction. Alcohol and drugs can profoundly affect different neurological circuits. Prolonged excessive alcohol use, for example, is believed to cause cause pervasive alterations in the brain's stress and anti-stress systems. These changes, in and of themselves, may lead to additional compulsive drinking.

The Addiction Project
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