Science of Addiction

Fact: Addiction is a chronic and complex brain disease.

What is Drug Addiction?
The National Institute of Drug Abuse (NIDA) defines addiction as a chronic, relapsing disorder characterized by compulsive drug seeking and use, despite harmful consequences.1

Addiction as a brain disease

Like diabetes, cancer and heart disease, addiction is caused by a combination of behavioral, environmental and biological factors. Chronic drug use interferes with and makes changes to brain circuitry and chemistry, and these changes lead to compulsive drug using behaviors. There is no cure for addiction, but there are many evidence-based treatments that are effective at managing the illness. Like all chronic illnesses, addiction requires ongoing management that may involve therapy, medication, and lifestyle changes.

ADDICTION is treatable and people in recovery from substance use disorder can go on to live healthy, successful, and meaningful lives.

Dopamine’s role in addiction

When we experience pleasure, our brain releases a neurotransmitter called dopamine. Dopamine is important for memory, learning, behavior, and motivation. When someone takes a drug, their brain produces large surges of dopamine – way more than gets produced as a result of a natural, pleasurable behavior like eating, listening to music, creative pursuits, or exercising – this is what makes a person “feel high”. The powerful reward sensation of “feeling high” creates a strong and rapid memory in the brain, associating drug use with extreme feelings of pleasure. With repeated exposure, it diminishes its sensitivity and makes it hard to feel pleasure from anything besides the drug.

Our brains are wired to reward us when we do something pleasurable.

The effects of long-term drug use

Continued, long-term drug use results in the brain reducing the number of dopamine receptors to adjust for the increased dopamine in the system. Over time, continued release of these chemicals causes changes in the brain systems involved in reward, motivation, and memory. Drug cravings and uncomfortable withdrawal symptoms like irritability, anxiety, depression, and insomnia make it more difficult for a person to stop using drugs. They may experience intense desires or cravings for the drug and will continue to use it, despite harmful or dangerous consequences. 2
A person who misuses drugs can lack motivation, feel depressed and is unable to enjoy things that they typically loved doing. They may also do things completely out of character or what they would ordinarily view as morally wrong in order to obtain the drug.
These changes in the brain can remain for many months after a person discontinues use. Fortunately, the damage is reversable with abstinence from the substances.

1 NIDA https://www.drugabuse.gov/publications/drugs-brains-behavior-science-addiction/drug-misuse-addiction#footnote
2 NIDA https://www.drugabuse.gov/publications/drugs-brains-behavior-science-addiction/drugs-brain