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(p. 129) Understanding Addiction 

(p. 129) Understanding Addiction
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date: 16 January 2021

Many people do not understand why individuals become addicted to alcohol or drugs, or how substances change the brain to foster compulsive substance abuse. They mistakenly view substance use disorders (SUD) as strictly a social problem and may characterize those who take drugs or use alcohol excessively as morally weak. One very common belief is that individuals with SUD should be able to just stop using if only they were willing to change their behavior. What people often underestimate is the complexity of addiction—that it is a disease that impacts the brain and because of that, stopping use is not simply a matter of will power. Through scientific advances we now know much more about how alcohol and drugs affect the brain, and we also know that addiction can be successfully treated to help people resume productive and healthy lives.

What Is a Substance Use Disorder?

Substance use disorders are chronic, often relapsing diseases that cause compulsive behaviors to seek out and use the substance, despite harmful consequences to the individual who is addicted and to those around her. Substance use disorders represent a brain disease because the abuse of substances leads to changes in the structure and function of the brain. Although it is true that for most people the initial decision to use alcohol or drugs is voluntary, over time the changes in the brain caused by repeated substance use can affect a person’s self-control and ability to make sound decisions.

It is because of these changes in the brain that it is so challenging for a person who is addicted to stop using substances. Fortunately, there are treatments that help people to counteract addiction’s powerful disruptive effects and regain control. One of the most effective treatments for substance use disorders are cognitive-behavioral therapy (CBT) approaches, including Relapse Prevention which the COPE treatment includes. Furthermore, research shows that combining behavioral or “talk” therapy with addiction medications, if available, can help to ensure treatment success.

Similar to other chronic, relapsing diseases, such as diabetes, asthma, or heart disease, substance use disorders can be managed successfully. And, as with other chronic diseases, it is not uncommon for a person to relapse and begin using substances again. Relapse, however, does not signal failure—rather, it indicates that treatment should be reinstated, adjusted, or that additional treatment may be needed to help the individual regain control, stabilize and recover.

(p. 130) What Happens to Your Brain When You Take Drugs?

Drugs are chemicals that tap into the brain’s communication system and disrupt the way nerve cells normally send, receive, and process information. Alcohol is also considered a drug. There are at least two ways that drugs affect the brain’s communication system: (1) by imitating the brain’s natural chemical messengers, and/or (2) by over-stimulating the “reward circuit” of the brain.

Some drugs, such as marijuana and heroin, have a similar structure to chemical messengers, called neurotransmitters, which are naturally produced by the brain. Because of this similarity, these drugs are able to “fool” the brain’s receptors and activate nerve cells to send abnormal messages. Other drugs, such as cocaine or methamphetamine, can cause the nerve cells to release abnormally large amounts of natural neurotransmitters, or prevent the normal recycling of these brain chemicals, which is needed to shut off the signal between neurons. This disruption produces a greatly amplified message that ultimately disrupts normal communication patterns.

Nearly all drugs (including alcohol), directly or indirectly target the brain’s reward system by flooding the circuit with dopamine. Dopamine is a neurotransmitter present in regions of the brain that control movement, emotion, motivation, and feelings of pleasure. The overstimulation of this system, which normally responds to natural behaviors that are linked to survival (e.g., eating, spending time with loved ones), produces euphoric effects in response to the drugs. This reaction sets in motion a pattern that “teaches” people to repeat the behavior of using substances.

As a person continues to use substances, the brain adapts to the overwhelming surges in dopamine by producing less dopamine or by reducing the number of dopamine receptors in the reward circuit. As a result, dopamine’s impact on the reward circuit is lessened, reducing the abuser’s ability to enjoy the substance and the things that previously brought pleasure. This decrease compels individuals with substance use disorders to keep using alcohol or drugs in order to attempt to bring their dopamine function back to normal. And, they may now require larger amounts of the substance than they first did to achieve the dopamine high—an effect known as tolerance.

Long-term substance abuse causes changes in other brain chemical systems and circuits as well. Glutamate is a neurotransmitter that influences the reward circuit and the ability to learn. When the optimal concentration of glutamate is altered by substance abuse, the brain attempts to compensate, which can impair cognitive function. Substances of abuse facilitate non-conscious (conditioned) learning, which leads the user to experience uncontrollable cravings when they see a place or person they associate with using substances, even when the substance itself is not available. Brain imaging studies of addicted individuals show changes in areas of the brain that are critical to judgment, decision-making, learning and memory, and behavior control. Together, these changes can drive a person with a substance use disorder to seek out and use alcohol or drugs compulsively, despite adverse consequences. In other words, the person ends up losing control over their use of alcohol or drugs.

(p. 131) Why Do Some People Become Addicted and Others Do Not?

No single factor can predict whether or not a person will develop a substance use disorder. Risk for addiction is influenced by a person’s biology, genetics social environment, and age or stage of development. The more risk factors an individual has, the greater the chance that taking using alcohol or drugs can lead to addiction. For example:

  • Biology. The genes that people are born with—in combination with environmental influences—account for about half of the vulnerability to develop a substance use disorder. Additionally, gender, ethnicity, and the presence of other mental health disorders, such as posttraumatic stress disorder (PTSD) and depression, influence risk for addiction.

  • Environment. A person’s environment includes many different influences, such as family and friends, socioeconomic status, and quality of life in general. Factors such as peer pressure, living with someone who uses alcohol or drugs, having alcohol or drugs in the home, ongoing physical or sexual abuse, access to treatment, and parental involvement can greatly influence the course of addiction in a person’s life.

  • Development. Genetic and environmental factors interact with critical developmental stages in a person’s life to affect addiction vulnerability, and adolescents experience a double challenge. Although taking drugs at any age can lead to the development of a substance use disorder, the earlier that substance use begins, the more likely it is to progress to more serious abuse. And because adolescents’ brains are still developing in the areas that govern decision-making, judgment, and self-control, they are especially prone to risk-taking behaviors, including trying substances of abuse.

For More Information

For information on understanding addiction, please see the full booklet, Drugs, Brains, and Behavior—The Science of Addiction, at

For more information on prevention, please visit

For more information on treatment, please visit To find a publicly funded treatment center in your state, please call 1-800-662-HELP or visit