The Neurobiology of Addiction: How Drugs Affect the Brain


Addiction and substance misuse were long viewed as character flaws, and those who struggled with them were labeled as “weak” or lacking in self-control. Thankfully, research has revealed their true nature as chronic illnesses—similar to diabetes, asthma, or hypertension—all of which require ongoing management.

Substance use causes changes to the brain that can lead to addiction, behavioral changes, and physical illness that require a holistic approach to healing. If you or a loved one is struggling with substance use, Immersion Recovery Center, an addiction treatment and detox center in Delray Beach, FL, can help. Professional treatment is critical to the recovery process and is available at our comfortable, modern facility. Here, we offer individual, family, and group therapy for Floridians and nonresidents alike, as well as multiple levels of care, including inpatient and outpatient programs. Contact us today to learn more about treatment options, payment alternatives, and more.

Addiction and the Brain

When you ingest a substance of misuse, whether it be orally, by smoking, or via injection, it interacts with your neurons (i.e., the message-carrying cells in the brain and other parts of the central nervous system), affecting the way they send, receive, and process signals. This process not only causes physical and mental impairment while the substance is active in the system, but also can result in a permanent rewiring of the brain that leads to dependence.

Addiction & Substance Use Disorder Defined

The American Society of Addiction Medicine defines addiction as a treatable, chronic medical disease involving complex interactions among brain circuits, genetics, the environment, and an individual’s life experiences.(1) People with addiction use substances or engage in behaviors that become compulsive and often continue despite harmful consequences.

The National Institutes of Health defines substance use disorder as “a treatable mental disorder that affects a person’s brain and behavior, leading to their inability to control their use of substances like legal or illegal drugs, alcohol, or medications.”(2) The NIH further notes that symptoms can range from moderate to severe with the most severe stage of SUD being addiction.

While addiction and substance use disorders are serious conditions, both are treatable. Immersion Recovery Center has created a unique and effective program that takes the best parts of traditional 12-step treatment and combines them with the highest standards of clinical and medical care, offering you the best tools for long-term recovery.

Which Brain Regions Are Involved in Addiction?

The brain comprises many interconnected regions that are responsible for specific functions, such as attention, self-regulation, perception, language, reward and pleasure, emotion, and movement, to name a few. Three of these regions are most involved and affected by substance use.

  • The basal ganglia are a group of brain structures that form the reward and pleasure center of the brain. This is the area from which euphoria or the “high” sensation caused by controlled substances emanates. These structures are also the seat of addiction.
  • Meanwhile, the amygdala is the region of the brain responsible for emotions, with feelings of stress, anxiety, and irritability originating in the extended amygdala. This part of the brain is responsible for the uncomfortable withdrawal symptoms that can develop if someone is dependent on a substance and stops or significantly decreases use.
  • The prefrontal cortex takes care of your ability to organize thoughts and activities, prioritize tasks, manage time, and make decisions. It is the part of your brain that exerts control over substance-taking.

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Dopamine & the Reward Pathway

Dopamine is a neurotransmitter that acts as a chemical messenger in the brain. It helps you feel enjoyment and pleasure, motivating you to engage in behaviors that will sustain or recreate those sensations. These sensations can be caused by a host of factors including  food, sex, alcohol, and controlled substances. In an article published by Psychology Today, behavioral psychologist Susan Weinschenk Ph.D. says dopamine increases your level of arousal and goal-directed behavior. This can result in substance-seeking behavior, as individuals continually seek out more of the substance that provides a sense of pleasure.(3) 

Role of Dopamine in Pleasure & Reward

Controlled substances influence the brain-reward pathway either by directly regulating the action of dopamine within the system or by altering the activity of other neurotransmitters that modulate the reward pathway.

Dopamine is released when the brain is anticipating a reward. When you experience a pleasurable stimulus, such as eating delicious food, playing video games, or taking a mind-altering substance, your brain is flooded by dopamine. The sensation creates a desire to further engage with this stimulus to extend or repeat the pleasurable sensations.

Dopamine Dysregulation in Addiction

Dopamine dysregulation syndrome (DDS) is an impairment of the reward system that develops when you engage in an activity that releases high levels of dopamine into the brain. You can develop DDS as a result of just about any addictive behavior, such as substance misuse, gambling, or sex.

Neurotransmitters & Their Role in Addiction

Neurotransmitters are the chemical messengers of the body, moving information from one nerve cell to another or to other cells. They are critical to body function, aiding in everything from keeping your heart beating to creating the sensation that alerts you that the object you are touching is hot.

Drug and alcohol use activates neurotransmitters that create the high and ultimately cause addiction. Neurotransmitter response varies from substance to substance, which is why different substances cause different highs.

Brain Changes with Chronic Drug Use

Drugs alter important areas of the brain, affecting mood, how you function in the world, decision-making, and even how your body works. 

Some of the most common effects of substance misuse are:

  • Cognitive decline
  • Memory loss
  • Mood changes and paranoia
  • Poor self/impulse control
  • Problems with heart rate, breathing, and sleep
  • Depression
  • Anxiety
  • Psychosis

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Cravings, Tolerance, & Withdrawal

At the heart of addiction is your body’s physical and emotional need to have a steady stream of a controlled substance in your body. Disrupt that flow, and your body will respond by developing an intense physiological and emotional need for more of the substance. Cut it off for too long, and your body will develop uncomfortable symptoms known as withdrawal.

You may also develop a tolerance to some drugs, causing you to need more to achieve the same effect.

Mechanisms Behind Drug Cravings

Addiction is caused by changes in the brain. Those alterations take place because a substance triggers an outsized response when it reaches the brain. For instance, opioids, cocaine, and nicotine trigger a flood of dopamine 10 times that of a nonaddictive, pleasurable experience such as watching a funny movie. The brain remembers the surge and associates it with the addictive substance. 

Development of Tolerance 

Over time, the brain adapts to the surges of dopamine that take place when using a certain amount of a substance. Your brain responds by producing less dopamine or eliminating dopamine receptors. Getting high becomes increasingly important, but you need increasing amounts of the substance to achieve the level of high you crave. This condition is known as tolerance.

The Role of Genetics in Addiction

Genetics plays an integral role in the development of addiction. In fact, Facing Addiction in America: The Surgeon General’s Report on Alcohol, Drugs, and Health states that genetic factors may account for 40 to 70 percent of individual differences in risk for addiction.(4) Multiple genes are likely involved in the propensity toward addiction, but, as of yet, scientists have only identified a few specific gene variants that make one more or less likely to develop an addiction. That said, no matter the cause of addiction, it’s a chronic yet fully treatable condition.

Neurobiological Aspect of Relapse & Recovery

Just as the brain is able to reorganize its structure and function in response to exposure to drugs and alcohol, with the correct treatment plan, it can also restructure itself to function without substances.

According to the National Institute on Alcohol Abuse and Alcoholism, medication and behavioral health treatments, or a combination of both, can promote functional brain recovery.(5) At Immersion Recovery in Delray Beach, FL, our multi-phase recovery program combines medication-assisted treatment (MAT) with a wide range of counseling and behavioral therapies to provide a whole-patient approach to substance use disorder treatment. Our skilled and compassionate team will design a program tailored to your needs, facilitating the healing of your brain, body, and spirit.

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Addiction is not a character flaw. It’s a chronic brain disease, and like other chronic conditions, such as diabetes or asthma, it requires ongoing care. If you or someone you love is struggling with addiction and needs help developing the tools necessary to manage it, Immersion Recovery Center, an addiction treatment and detox center in Delray Beach, FL, can help. 

Our holistic approach and expert medical and clinical care provide a strong foundation for your long-term recovery. The facility’s caring medical, clinical, mental health, and recovery professionals have decades of combined experience to help you heal physically, emotionally, and spiritually. Our customized, evidence based care includes a host of treatment options as well as various forms of therapy, group support, and case-management services. 

We understand that behavioral health and alcohol and substance use disorder treatment is not a one-size-fits-all solution, and we are dedicated to helping you find the treatment option that makes the most sense for your unique clinical needs. Take your first step toward recovery today. Reach out to learn more about treatment options, insurance coverage, and more.

  1. American Society of Addiction Medicine. Definition of Addiction. Available at:
  2. National Institutes of Health. What does it mean to have substance use and co-occurring mental disorders? Available at:
  3. Psychology Today. The Dopamine Seeking-Reward Loop. Available at:
  4. National Library of Medicine. Facing Addiction in America: The Surgeon General’s Report on Alcohol, Drugs, and Health.” Available at:
  5. National Institute of Alcohol Abuse and Alcoholism. Neuroscience: The Brain in Addiction & Recovery. Available at:

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Serving as the Inpatient Clinical Director at Immersion Recovery Center, Susan will work directly with staff members, clients, and family members to ensure the clinical program remains as effective and individualized as possible. Susan is no stranger to the fields of behavioral health and addiction. She has over 25 years of experience, working in an inpatient setting, an outpatient setting, acute stabilization and nearly all other settings in the realm of addiction recovery.