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Science of Addiction: Neurobiology and Substance Abuse

By Dr. Rostislav Ignatov, Chief Medical Officer 

Graphic illustrating the interplay between genetics and environmental risk factors in addiction

Addiction is a multifaceted problem that affects millions of Americans. According to the 2021 NSDUH, approximately 46.3 million individuals aged 12 or older met the DSM-5 criteria for a substance use disorder (SUD) in the past year. 

But what exactly is addiction, and how does it work? By understanding the science of addiction, we can recognize the signs, provide support, and explore effective treatment for ourselves and those struggling with the harmful consequences of drug use. 

Key Takeaways 

Understanding the science of addiction is a stepping stone for prevention, support, and healing. Here’s what you need to know: 

● Addiction is a complex interplay between your brain, genes, and environment. 

● There are several ways to manage and treat addiction, including detox, therapy, and medication. 

● Having a strong support system and relapse prevention plan can help regain control of life. 

Keep reading to better understand your brain and how addiction changes your neurobiology.

Understanding Addiction 

Addiction is a brain disorder that makes a person dependent on a substance or behavior, like drugs or alcohol, making quitting hard. It’s a complicated issue that affects many people, impacting their health, relationships, and overall well-being. 

When someone is addicted, they experience intense cravings and have difficulty controlling their use, even if it causes problems in their life. Addiction is not a choice but a chronic brain disease that leads to functional changes in the brain. 

Why the Science of Addiction Matters 

Before diving in, consider why understanding the science of addiction matters. When we understand how addiction works, we can: 

Fight Stigma: Many people think substance use disorder (SUD) is due to a lack of willpower. Knowing it’s a brain disease helps fight this misconception. 

Support Loved Ones: If someone you care about is struggling with an addiction, understanding the science can help you be more compassionate and supportive. 

Make Smarter Choices: When you know how addictive substances can mess with your brain, you might think twice before trying them. 

Inside the Brain: How Addiction Takes Hold 

We often hear that our brain is like a supercomputer. It’s true! Our brain runs the show – from tying a shoe to solving math. But what happens when something like addiction comes into play? 

The Reward System 

Your brain wants you to live. It ensures you feel good when you do something fun which benefits survival, like eating your favorite food or hanging out with friends. 

The reward system in your brain uses a neurotransmitter, dopamine, to send messages to your brain and body that this activity feels good. When something feels good, you are likely to repeat it. 

How Drugs and Alcohol Hijack the Reward System 

Here’s where things get tricky. Drugs and alcohol trick the brain into sending way too much dopamine. At first, this seems fun. You experience a wave of pleasure every time you consume the drug, and your brain produces more and more dopamine. Over time, the brain gets used to this new level of dopamine. Normal fun things don’t feel as good anymore.

This is how substances hijack the brain’s reward system. They mess up the balance of dopamine, and suddenly the brain is hooked on drugs and alcohol, leading to addiction. 

Understanding Addiction: Insights from Neurobiology 

Addiction doesn’t just mess up the fun in your brain; it can actually change how your brain works. Think of your brain as a puzzle, each piece fitting perfectly. But substance abuse is like forcing a piece that doesn’t fit, which can twist and change the whole picture. 

Let’s dig deeper into the science behind this – the neurobiology of addiction. How Substance Abuse Alters Brain Chemistry 

When someone uses drugs or drinks too much, the brain changes. It tries to adapt. This is called neuroadaptation. The brain says, “Okay, this is the new normal.” The brain adapts to accept the heightened level of dopamine as a base level. Now when you drink or use drugs, you don’t experience a high. The brain now needs more of the substance to feel the same effects. This is called tolerance. 

As the brain adapts to the drug, it starts depending on it to function. 

Imagine relying on coffee to wake up every morning. If you don’t get it, you feel grumpy and tired. You may crave coffee or other sources of caffeine and experience headaches and irritability. That is withdrawal. 

Substance abuse has altered how your brain functions. Without a steady supply of the drug, your brain threatens to shut down. 

Substance Abuse and Neurobiology: Common Examples 

Different drugs can impact your brain and body in different ways. Let’s take a closer look at three common culprits: alcohol, opioids, and stimulants. 


Alcohol can act like a mood amplifier. At first, you might feel happy and relaxed. But as you drink more, it starts to slow down your brain. Your speech can get slurry, and you might have trouble walking or thinking clearly. 

With time, drinking alcohol can change your brain. It might make you feel anxious or sad without a drink. Your brain starts to crave alcohol, and it can be tough to say no. This is how addiction to alcohol sets in.


Opioids, including oxycodone, hydrocodone, and methadone, are painkillers. They can block pain and make you feel calm and happy. But they can also slow down your breathing and make you sleepy. Too much can even stop your breathing altogether. 

When people use opioids, their brains get used to the drug. They need more to feel good. Without the drug, they feel really sick. This is how addiction to opioids happens. 


Stimulants like cocaine and methamphetamine can make you feel energized and happy. It’s like having a turbo button for your brain. But they can also make your heart race and make you feel anxious. 

With stimulants, the brain gets hooked on high energy. It starts to need the drug to feel awake and happy. Without it, the person feels tired and depressed. This is how addiction to stimulants can develop. 

Reclaiming Lives: Treatment and Recovery Options 

Breaking free from addiction is like finding your way out of a maze. It’s tough, but people can make it through with the right tools and support. There are many ways to tackle addiction. 

Let’s explore how treatment, support systems, and managing relapses can help someone exit the maze of addiction. 

Approaches to Treatment 

Drug addiction often requires a mix of treatment approaches. Treatment may include: 

Medication-Assisted Treatment (MAT): MAT uses medications to balance the brain and reduce cravings. It helps keep patients stable during treatment so they can slowly wean off their drug of choice. MAT gently guides the brain to return to previous dopamine levels. 

Behavioral Therapies: Therapies, like CBT, help people change how they think and act. They learn new ways to cope with stress and avoid triggers that make them want to use substances. 

Rehab Programs: Rehab programs, like inpatient and outpatient treatment programs, offer a safe space for people to focus on recovery. They have therapy, education, and support to help them get back on track. 

The Role of Support Systems 

The human brain is built to be social. Having a robust support system can help you overcome drug dependence.

Family and Friends: Knowing that family and friends are rooting for you can be a huge boost. They can be there to cheer you on and help you stay focused on recovery. 

Support Groups and Therapy: Sometimes, it helps to talk to others who are also finding their way out of the maze. Support groups and therapy can offer a space to share stories and tips for recovery. 

Relapse and Management 

Recovery is not a straight climb. Sometimes there are stumbles and falls. But that doesn’t mean you can’t keep climbing. 

Understanding the Relapse: Slipping up doesn’t mean failure. It’s often part of the journey. The key is to learn from it and keep moving forward. 

Strategies for Relapse Prevention: This includes having a plan for dealing with cravings, avoiding triggers, and knowing who to call for help if you’re struggling. 

Addiction Changes the Brain 

The main theory of addiction is the “Brain Disease Model.” When people use drugs or alcohol, it can change how their brains work. These brain changes can make it extremely hard for them to stop using the substance. They might feel like they need drugs to feel normal. 

This theory helps us understand why quitting is so tough and removes the blame from people with this chronic disease. 

Addiction is complex because everyone’s brain is unique, like a fingerprint. Psychological factors, like how patients deal with stress, genetic factors, like a family history of substance abuse, and social factors, like peer pressure, all contribute to substance abuse. 

However, the changes addiction makes to the brain separate addiction from substance abuse. Neurobiological changes are what make addiction so deadly.