Get the facts about how addiction affects our bodies, our brains, and our behavior, while learning about the biological and psychological factors that often drive addiction.
What is addiction?
The National Institute of Drug Abuse (NIDA) defines addiction as a chronic, relapsing brain disease that is characterized by compulsive drug seeking and use, despite harmful consequences.1
In the United States, 8–10% of people over the age of 12 are addicted to alcohol or other drugs. That’s approximately 22 million people.2 (Cigarette smoking is also an addiction that kills people.)
Addiction is chronic—but it’s also preventable and treatable
When a disease is chronic, that means it’s long-lasting. It can’t be cured, but it can be managed with treatment. Other examples of chronic diseases include asthma, diabetes, and heart disease.
It is critical that treatment simultaneously addresses any co-occurring neurological or psychological disorders that are known to drive vulnerable individuals to experiment with drugs and become addicted in the first place. Otherwise, the best addiction treatment in the world alone is not effective for those with co-occurring illnesses.
Addiction is a disease
Respected institutions like the American Medical Association and the American Society of Addiction Medicine define addiction as a disease.3 Studies published in top-tier publications like The New England Journal of Medicine support the position that addiction is a brain disease.4
A disease is a condition that changes the way an organ functions. Addiction does this to the brain, changing the brain on a physiological level. It literally alters the way the brain works, rewiring its fundamental structure. That’s why scientists say addiction is a disease.
Although there is no cure for addiction, there are many evidence-based treatments that are effective at managing the illness. Like all chronic illnesses, addiction requires ongoing management that may include medication, therapy, and lifestyle change. Once in recovery from substance use disorder, a person can go on to live a healthy and successful life. Addiction is treatable, and recovery should be the expected outcome of treatment.
How does addiction change the brain?
The human brain is wired to reward us when we do something pleasurable. Exercising, eating, and other pleasurable behaviors directly linked to our health and survival trigger the release of a neurotransmitter called dopamine. This not only makes us feel good, but it encourages us to keep doing what we’re doing. It teaches our brains to repeat the behavior.5
Drugs trigger that same part of the brain—the reward system. But they do it to an extreme extent, rewiring the brain in harmful ways.
When someone takes a drug, their brain releases extreme amounts of dopamine—way more than gets released as a result of a natural pleasurable behavior. The brain overreacts, reducing dopamine production in an attempt to normalize these sudden, sky-high levels the drugs have created. And this is how the cycle of addiction begins.
Once someone is addicted, they’re not using drugs to feel good — they’re using drugs to feel normal
Studies have shown that consistent drug use severely limits a person’s capacity to feel pleasure. at all.6 Over time, drug use leads to much smaller releases of dopamine. That means the brain’s reward center is less receptive to pleasure and enjoyment, both from drugs, as well as from every day sources, like relationships or activities that a person once enjoyed. Once the brain has been altered by drug use, it requires more and more drugs just to function at a baseline level.7
Withdrawal is a painful, whole-body experience
Withdrawal happens when a person who’s physically dependent upon a substance stops taking it completely: either in an attempt to quit cold turkey, or because they don’t have access to the drug. For pain-management and opioid users in particular, even if a user is not addicted, they can still become dependent on the medication, and they would still experience withdrawal. Someone in withdrawal feels absolutely terrible: depressed, despondent, and physically ill.
An addicted brain causes behavior changes
Brain imaging studies from drug-addicted individuals show physical, measurable changes in areas of the brain that are critical to judgment, decision making, learning and memory, and behavior control. Scientists believe that these changes alter the way the brain works, and may help explain the compulsive and destructive behaviors of addiction.8
A promising student might see his grades slip. A bubbly social butterfly might suddenly have trouble getting out of bed. A trustworthy sibling might start stealing or lying. Behavioral changes are directly linked to the drug user’s changing brain.
Cravings take over. These cravings are painful, constant, and distracting.9 The user starts seeking out drugs, no matter the consequences, often resulting in compulsive and destructive behaviors. Especially given the intensity of withdrawal symptoms, the body wants to avoid being in withdrawal at all costs.
What fosters addiction? Science says there are three main factors.
The first time a person tries alcohol or another drug, it’s a voluntary choice. But at some point during use, a switch gets flipped within the brain and the decision to use is no longer voluntary. As the Director of the National Institute on Drug Abuse puts it, their brains have been hijacked.
Anyone who tries a substance can become addicted, and research shows that the majority of Americans are at risk of developing addiction. Over 40% of 13–14 year olds, and over 75% of 17–18 year olds, report that they’ve tried alcohol. What’s more, 42% of 17–18 year olds report that they’ve tried illicit drugs.10
After initial exposure, no one chooses how their brain will react to drugs or alcohol. So why do some people develop addiction, while others don’t?
The latest science points to three main factors.
All this scientific evidence points to one bottom line: addiction is not a moral failing.
Addiction is not a choice. It’s not a moral failing, or a character flaw, or something that “bad people” do. Most scientists and experts agree that it’s a disease that is caused by biology, environment, and other factors.
Harmful consequences, shame, and punishment are simply not effective ways to end addiction. A person can’t undo the damage drugs have done to their brain through sheer will power. Like other chronic illnesses, such as asthma or type 2 diabetes, ongoing management of addiction is required for long-term recovery. This can include medication, behavioral therapy, peer-support, and lifestyle modifications.
Learn more about evidence-based prevention, treatment, and recovery methods.
1. National Institute on Drug Abuse. The Science of Drug Abuse and Addiction: The Basics.
2. Grant B, Saha TD, Ruan WJ. “Epidemiology of DSM-5 Drug Use DisorderResults From the National Epidemiologic Survey on Alcohol and Related Conditions–III.” The Journal of the American Medical Association, January 2016.
3. ASAM. Definition of Addiction.
4. Volkow ND, Koob GF, McLellan AT. “Neurobiologic Advances from the Brain Disease Model of Addiction.” The New England Journal of Medicine, 28 January 2016.
5. “Drugs, Brains and Behavior: The Science of Addiction.” National Institute on Drug Abuse, July 2014.
6–7. Volkow ND, Koob GF, McLellan AT. “Neurobiologic Advances from the Brain Disease Model of Addiction.” The New England Journal of Medicine, 28 January 2016.
8. “Drugs, Brains and Behavior: The Science of Addiction.” National Institute on Drug Abuse, July 2014.
9. Volkow ND, Koob GF, McLellan AT. “Neurobiologic Advances from the Brain Disease Model of Addiction.” The New England Journal of Medicine, 28 January 2016.
10. Swendsen J, Burstein M, Case B. “Use and Abuse of Alcohol and Illicit Drugs in US Adolescents: Results of the National Comorbidity Survey–Adolescent Supplement. The Journal of the American Medical Association, April 2012.
11. The National Center on Addiction and Substance Abuse. Addiction Risk Factors.
12. “Drugs, Brains and Behavior: The Science of Addiction.” National Institute on Drug Abuse, July 2014.
13. “Drugs, Brains and Behavior: The Science of Addiction.” National Institute on Drug Abuse, July 2014.