The Science of Addiction – “Get the Facts”

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.(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.

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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 pleasureat 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.

Three Main Factors Addiction

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.

Original article here on

Study: In heroin addiction, glial cells play key roles in regulating the motivation for the drug

Findings suggest these specialized cells help rewire the addicted brain

BUFFALO, N.Y. — Scientists studying addiction know that heroin and other opioids induce plasticity in brain cells. Now, University at Buffalo researchers have made the novel discovery that in certain types of brain cells, drug-induced plasticity can work to reduce, rather than boost, motivation for heroin.

By providing new insights into how addiction changes the brain, the research could lead to novel approaches to treatments and potential new targets besides neurons.

“Most therapies have focused on the blocking or activating of receptors that bind drugs like heroin,” explained David Dietz, PhD, senior author of the paper and associate professor in the Department of Pharmacology and Toxicology in the Jacobs School of Medicine and Biomedical Sciences at UB. “While that approach may be effective in the short-term, it doesn’t get to the fundamental problem of what is addiction and how to prevent it, as well as prevent relapse.”

Published online last month in Neuropsychopharmacology, the paper describes how glial (non-neuronal) cells regulate both cellular and behavioral responses to heroin.


“Not much is known about glial cells in the context of addiction” said Dietz, a faculty member with UB’s neuroscience program. “In the addiction field, most neuroscientists focus on neurons. Very rarely have they studied glial cells in psychiatric diseases. This work demonstrates an essential role of glia in addictive behaviors, and offers us the ability to provide a new set of targets for future therapies toward the treatment of addiction.”

Dietz and his colleagues decided to study the potential role of glial cells in addiction when they found that RNA sequencing of tissue from heroin-addicted animals revealed changes in genes that are traditionally markers for a type of glial stem cell called oligodendrocyte precursor cells or OPCs.

Opiates and the prefrontal cortex

The research is likely the first to investigate how opiates affect adult OPCs in the brain’s prefrontal cortex, which is involved in complex cognitive behaviors and is a main target of addictive drugs.

“We found that many of the genes regulated by heroin aligned with the profile of OPCs, so something was going on with them,” he said.

OPCs, he explained, are cells that often become myelin, which is critical for efficient communication between neurons.

Dietz collaborated with his colleague Fraser Sim, PhD, associate professor in the Department of Pharmacology and Toxicology in the Jacobs School, co-author on the paper. In 2014, Sim identified one of the genes, SOX10, as a “master switch” for the differentiation of these stem cells towards myelination.

To determine what was happening when genes encoding OPCs were exposed to heroin, the scientists overexpressed them in addicted laboratory animals using viral gene therapy.

Compensatory effect

The result was surprising: when either of the two genes, SOX10 or BRG1, was overexpressed, the animals’ motivation to take the drug was reduced.

“To our surprise, it reduced their drug-taking behavior,” said Dietz. “It looks like the brain is trying to reconnect and possibly readapt myelin to normalize function, although that would need to be directly tested in future studies.”

One way to think of what may be happening, he explained, is to imagine that the brain is responding to exposure to drugs of abuse by attempting to reconnect with the brain’s other reward centers.

“As with any part of the body that sustains an insult, it seems that the addicted brain is trying to fix what went wrong,” he said. “Our hypothesis is that after exposure to heroin, the brain starts to upregulate OPCs in an attempt to fix the altered connectivity that occurs in the addicted states. It is possible that when we facilitated OPCs, we may have reversed some of the disconnect between the prefrontal cortex and the brain’s other reward regions.”

The research was funded by the National Institute on Drug Abuse of the National Institutes of Health.

Along with Dietz and Sim, other co-authors are: J.A. Martin, A. Caccamise, C.T. Werner, R. Viswanathan, J.J. Polanco, A.F. Stewart, S.A. Thomas, all of the Department of Pharmacology and Toxicology in the Jacobs School.

Original article here.  Release Date: January 26, 2018

Online Course: What is Addiction? Tonight 6-7pm

The Addiction Policy Forum invites you to join them for a free online course “What is Addiction? Understanding the Brain Science of Addiction” TONIGHT, February 7th, 2018 from 6:00 PM to 7:00 PM EST with Dr. Maureen Boyle, Chief Scientific Officer at the Addiction Policy Forum.

Date: Wednesday, February 7, 2018
Time: 6–7 p.m. ET
Register for the free webinar here.

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