Drug Addiction And Your Brain

Addiction is complex, but the biological underpinnings of this disease is strongly found on how it alters the brain chemistry. What do people need to know about how addiction affects the brain? Read to learn more.

There are two main schools of thought regarding how people view addiction. Others think that addiction is a choice–those who suffer from it have some form of “moral failing” and they can quit on their own will. However, modern researchers have been leaning towards addiction as a disease–a medical condition that affects the brain, in particular.

Understanding The Brain On Drugs

In order to understand how does drug addiction affect the brain, it can help to know about how some of its parts are responsible for controlling and reinforcing behavior.

What causes addiction on the brain?

It is interesting to note that our brains register feelings of pleasure in a general manner. Whether we exercised, had a good meal, experienced a relaxing vacation or had an intimate encounter, the body’s mechanism towards associating ‘feel-good’ experiences remain similar: There is a release of a chemical called dopamine in the lower part of the brain called the nucleus accumbens. The second type of interaction is when drugs mimic the structure of dopamine to trick the brain’s receptors.

In the right balance, dopamine is a neurotransmitter that can bring a host of effects, such as:

  • Experiencing pleasurable emotions (euphoria)
  • Better muscle coordination
  • Improved working memory
  • Realistic pain processing
  • Better social functioning

This naturally occurring chemical needs to be in the right amount on each designated part of the brain in order to have its positive effects. However, for people with addictions, the release of dopamine is in a “overdrive” state, caused by different mechanisms of action produced by the intake of drugs.

This repeated action of dopamine release brings incredible pleasure and relief. As a result, addiction develops because of genetic tendencies and external factors help reinforce substance-seeking behavior. In a sense, the brain is ‘hijacked’ and artificially programmed to gradually present larger amounts of dopamine for pleasure.

The changes in this minute level ultimately affects various parts of the brain, which essentially regulates other parts of the body.

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How Does Addiction Affect The Brain: Functions That Change

The dopamine imbalance causes many issues in certain brain areas. Below, you can find each brain area and the notable effects caused by addiction:

Limbic system: Effects of drugs on the brain

The limbic system in the brain is comprised of various parts that control most of our emotional responses and memory retention. Do drugs affect the limbic system? In case you’re wondering what part of the brain controls addiction, the limbic system is also known to control the use of alcohol or drugs when an individual is suffering from substance use disorder. Substance-seeking behavior is often reinforced by emotional and memory triggers from the limbic system such as:

  • Experiencing unhealthy stress, sadness, and other negative emotions
  • Seeing familiar places and people you abused substances with
  • Being immersed in situations where you’re emotionally set to give in to drugs or alcohol (drinking events, parties, etc.)

Specifically, each part of the limbic system are affected by continued drug or alcohol use:


The hypothalamus is the part of the brain responsible for the regulation of many functions such as hunger, thirst, pain, and pleasure. It receives information through the nerves and sends out a response to regulate and normalize each level of function.

In the drug-addicted brain, the hypothalamus is affected due to abnormal levels of brain chemicals. Since the hypothalamus controls the body’s autonomic nervous system, many of the functions of the vital organs will be affected such as:

  • Breathing: Shallow or labored breathing, slowing down, or cessation of breathing
  • Heart functions: Fast or slow heart rate, irregular heartbeat, heart palpitations
  • Blood pressure: Low or high blood pressure

Additionally, the hypothalamus is responsible for bodily responses to emotional triggers. For example, you may feel your heart racing or you may have sweaty palms before speaking in public. You may cry upon watching an inspirational movie, or you may experience a headache when in great distress.


The hippocampus is a horn-shaped structure that is known for converting short-term memory into long-term memory. It sorts out experiences in association with the other parts of the limbic system in order to cement memories that will last for a lifetime.

People with addiction may also suffer from hippocampal damage, such as:

  • Short-term memory loss
  • Memory retrieval problems
  • Gradual fading of long-term memory

Individuals who abuse alcohol or drugs for a long period of time are at higher risk for memory-related conditions such as Alzheimer’s Disease or dementia as well. If they have a family background of these neurological disorders, substance use disorder may advance or trigger the problem easily.


The amygdala is a nut-shaped structure just below the hippocampus. It is the part of the brain that is responsible for the response to stimuli. An addiction sufferer may have impaired amygdala function that makes them have either over-response or under-response to external stimuli.

For example, people abusing drugs or alcohol may act unnaturally aggressive over little conflicts. In some instances, people appear emotionless or unaware of their surroundings.

Other parts of the brain

Aside from the three major parts of the limbic system, there are also related brain areas that can dysfunction with long-term drug use.

  • Cingulate gyrus: This part serves as a pathway between the hypothalamus and the hippocampus. A drug-impaired cingulate gyrus may have strong associations between many stimuli and triggers to substance use.
  • Ventral tegmental area: These are also called dopamine pathways. People who abuse drugs and alcohol often have damage in this area because they cannot easily find pleasure through natural means. However, the continuous use of substances further adds to the problem of tolerance and dependence.
  • Basal ganglia: This area of the brain is known to control reward-seeking behavior. The basal ganglia becomes impaired when the only association of getting a reward is through the abuse of substances.
  • Prefrontal cortex: The prefrontal cortex is responsible for thoughtful decision-making and calculation of risks. For people with addictions, the prefrontal cortex functions differently, as decision-making turns more into an emotional rather than a logical response.

When looking at the big picture, we can view the addictive substance as an unwelcome guest in an otherwise perfectly performing harmonic orchestra. As the drug or alcohol sends out abnormally high levels of feel-good chemicals or mimics them in some way, these other brain areas which control the rest of the body get disrupted as well.

What causes addiction in the brain?

There is no single answer as to why some people get addicted easily and others do not. There are many factors that influence the development of an individual’s addiction, such as genetic predisposition, type of substance use disorderd, frequency or length of use, and even environmental factors.

What is clear, however, is how addiction develops from virtually nothing into a chronic disease. In a particle level, it all starts with the brain’s receptors binding to drugs that mimic or stimulate feel-good chemicals. For people who are susceptible, this impacts their limbic system, reinforcing the person to keep on looking for the same substances that damage their brain and make the problem worse. The cycle goes on repeat until the person experiences an overdose and other life-threatening situations.

The good news is, brain changes during substance use disorder can be prevented and even reversed through evidence-based treatment options. By seeking the help of addiction specialists, it is possible to reprogram your brain after a substance use disorder problem.

It’s All In The Brain: Rethinking The Impact Of Addiction

As researchers continuously discover the brain mechanisms that influence addictive behavior, it is about time that we change the narrative of seeing addiction as a choice. We should incline towards seeing how it truly affects peoples’ brains on a biological and psychological level, as many modern studies show. This is the only way to help us remove the stigma associated with addiction, and eventually encourage individuals to get the help they deserve.

Medical disclaimer:

Sunshine Behavioral Health strives to help people who are facing substance abuse, addiction, mental health disorders, or a combination of these conditions. It does this by providing compassionate care and evidence-based content that addresses health, treatment, and recovery.

Licensed medical professionals review material we publish on our site. The material is not a substitute for qualified medical diagnoses, treatment, or advice. It should not be used to replace the suggestions of your personal physician or other health care professionals.

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