The Addict’s Brain: A Closer Look at the Science of Addiction | AspenRidge

The Addict’s Brain: A Closer Look at the Science of Addiction


To many non-addicts, drug addiction seems like something that the addict chooses. In reality, however, addiction is a neurological disease that affects the brain in profound ways. As someone becomes increasingly dependent on drugs or alcohol, they actually lose the cognitive ability to understand exactly how dangerous the drug is.

It’s no surprise to find out, then that the word “addiction” actually derives from a Latin term meaning “bound to” or “enslaved by”. While there is a certain amount of choice involved in using and abusing drugs, addiction can quickly become a prison that’s difficult to escape from.

An Ever-changing Perception of Addiction

Over the course of the last century, scientific attitudes toward addiction have evolved drastically. In the early 1900’s, researchers came to the conclusion that people developed addictions because they lacked some kind of moral compass. They believed that the only way to treat addiction was to punish addicts or, at least, to help them develop a sense of willpower.

Fortunately, scientists have scrapped that hypothesis. Vast amounts of research have been conducted into the root causes and potential treatments of addictive behavior. Today, the majority of scientists agree that addiction is physical illness rooted in chemical dependency.

So what do we know about addiction now? How does it physically change the human brain? If it’s much more complicated than a matter of willpower, what makes quitting drugs so difficult?

Understanding the connection between addiction and the brain is important for both addicts and scientists. The more we know about how drugs affect us on a neurological level, the better we’ll we able to prevent and treat drug addiction.


Drug Abuse: Bamboozling the Reward System

There are three key parts of your brain affected by drugs. The first is the limbic system, which keeps track of the things that you interact with throughout your life. When you have a significant encounter with something, your limbic system programs a response to that thing. If you’re attacked by a dog at a young age, for example, your limbic system is the part of your brain that reminds you to be careful around dogs whenever you encounter one.

An important function of the limbic system is its “reward circuit”. The reward circuit is what reminds us to repeat behaviors that we find pleasurable. If you eat a cookie for the first time, it’s likely that you’ll enjoy it. When you enjoy something, your brain produces neurotransmitters called dopamine and serotonin. These are the chemicals that make you feel happy. So, if you eat a chocolate chip cookie and your brain produces a rush of serotonin, your limbic system takes note of the fact that you enjoy cookies and reminds you that you should probably eat more in the future.

A Skewed Sense of Pleasure

Drugs, of course, can make you feel pretty good, especially when you use them for the first time. When you take your first sip of alcohol or your first hit of marijuana, your brain experiences a big rush of serotonin and dopamine. Those chemicals cause you to feel pretty euphoric and your limbic system recognizes that the experience was pleasurable.

The big problem, however, is that drugs and alcohol produce an unnatural amount of neurotransmitters. No food, activity or situation can produce the same level of dopamine and serotonin that drugs do. So, after you’ve used a drug like heroin, your limbic system is going to crave it because no other activity could really compare. A drug habit can easily turn into an addiction if you repeatedly feed those cravings.

Rewiring the Midbrain

The second part of the brain that plays a crucial role in addiction is the midbrain. Your midbrain is responsible for all of your survival functions—seeing, listening, fight-or-flight, etc. Remember that dog that we talked about earlier…the one that bit you when you were a kid? If your limbic system sends the signal that you’re in danger of being bitten again, your midbrain is the part that prompts you to get the hell out of there.

Your midbrain is solely concerned with your survival. Everything it does is in order to keep you alive right now. Your midbrain works in the short-term, only taking into account your immediate surroundings. It isn’t concerned with your retirement savings or even what you’re having for dinner. It’s just there to make sure that you don’t die in the next 10-15 seconds. It’s often referred to as the “primitive brain” because it is responsible for driving our most instinctive actions.

Using to Survive

Drug use becomes a serious problem when your midbrain is affected by the substance. In other words, if your brain becomes accustomed to having a certain drug present in it, your midbrain will start to recognize the substance as something you need to survive.

This means that, once you’re addicted to a drug, you’ll find yourself compulsively seeking it out for reasons other than pleasure—you’ll be seeking it out because your midbrain is demanding it.

An Overthrown Executive Function

The third, and final, part of the brain involved in addiction is the prefrontal cortex. It helps to think of your prefrontal cortex as the CEO of your brain. It’s where all of your decisions are made.

If you find yourself standing on a car lot thinking about buying that Mustang you’ve always wanted but is out of your price range, you’ll use your prefrontal cortex to decide. It’s the part of your brain that uses logic and reasoning to determine whether something is a good or a bad idea.

Ideally, the prefrontal cortex would work to remind you that drugs are dangerous and that you probably shouldn’t use them. However, many of us aren’t that lucky.

When the Decision is Out of Your Hands

Usually, our brain can subconsciously weigh the benefits and downsides of using drugs. Once we become addicted, though, we lose the ability to make rational decisions. As the drug becomes a stable presence in the brain, the prefrontal cortex loses its ability to inject reason and logic into the decision-making process.

Ultimately, the prefrontal cortex is overpowered once the midbrain is driven by drugs. This is the main reason why addicts are unable to quit even when they know that they’re addicted and that a substance is causing them harm. No matter how much drugs might threaten the addict’s personal life, professional life or safety, addicts will continue to feed their cravings. It is not until an addict commits to recovery that they can retrain their brain to function properly without the drug in their system.

Genetics: Why are Some Brains More Prone than Others?

There has been a debate about the connection between genetics and addiction for quite a long time. Many researchers have claimed that an individual’s likelihood of becoming addicted to drugs is determined by their environment—whether or not the people around them use drugs and how easily the drugs can be obtained.

The American Psychological Association, however, believes that genetics is a large factor in addiction. The organization states that at least 50% of an individual’s susceptibility to addiction can be explained by genetics.

One member, Dr. Nora Volkow, points out that there are several different types of dopamine receptors in the brain. The quantity of each type varies in different brains. In Dr. Volkow’s research, she found that individuals with less of the second dopamine receptor (known as D2 in the medical community) are far more likely to become addicted to drugs. She acknowledges, however, that environmental factors will always play a role due to the fact that the addict must have access to drugs and choose to use them.

Other doctors have taken up an interest in the D2 dopamine receptor, as well. In Nature Neuroscience, a journal that studies the animal brain, Paul J. Johnson and Paul J. Kenny published research that suggests D2 is the site where compulsive behavior (in their case, overeating) begins. A lack of D2 receptors, therefore, would result in a dysfunctional reward system.

Could Genetic Testing Be the Key to Addiction Prevention?

While we’ll have to wait and see what comes of this research, many doctors have already advocated for increased genetic testing among drug addicts.

Medical professionals like Dr. Volkow believe that testing the genes of addicts would provide researchers with a clearer view of the connection between addiction and genes. “Understanding the complex interactions between the factors involved in drug abuse and addiction is critical to their effective prevention and treatment,” she says.

The Brain in Recovery: What Happens When You Quit?

The research is still out on whether the human brain can ever fully recover from an addiction. After all, many addicts report having cravings for years after they complete treatment. This is likely due to the fact that cravings are closely tied to the memory of using. Unfortunately, some memories don’t go away.

Even if a cocaine addict lost their job, severed important relationships and caused major problems for themselves while using, their brain will always relate the drug with pleasure on some level. A triggering event, such as the image of someone else enjoying cocaine on television, could cause them to crave the drug years after they quit.

The human brain is resilient enough to recover from damage imposed on it by the overflow of neurotransmitters created by drugs. This is not to say, of course, that any severe brain damage caused by the drug (“wet brain” from excessive drinking, for example) will be magically cured once the addict stops using. It is to say, though, that an addict who suffers no long-term damage during the time that they use will eventually have normal dopamine levels after they’ve been clean for a few years.

However, because the brain stores memories of drug use, former addicts are able to re-enter addiction without any buildup. A person who becomes addicted to cigarettes would need to smoke for an extended period of time before they became chemically dependent on nicotine. An individual who quit smoking for 5 years but relapsed on cigarettes, however, could find themselves addicted again after a single smoke.

Targeting the Brain in Addiction Treatment

The tendency among addicts to relapse (data estimates relapse rates to be anywhere between 40% and 60%) has led many scientists to seek ways of ending addiction once and for all. Whereas some doctors believe that replacement medications or vaccines are the keys to tackling addiction, there is no denying the fact that people who take these meds remain susceptible to relapse.

While the research is skim in terms of relapse rates, it’s safe to say that a portion of those who return to using every year tried medically-assisted treatment before they decided to use again.

Restoring the Prefrontal Cortex

In a recent National Geographic article, writer Fran Smith profiled a number of doctors who are experimenting with new and alternative methods of treating an addicted brain. One group profiled in the article is currently working on an addiction treatment method that stimulates the prefrontal cortex using a method called optogenetics.

In the ontogenetic method, the prefrontal cortex is manipulated via fiber optic light. The light stimulates the executive function of the brain, essentially prompting it to become more dominant than the drug-craving midbrain. An addict with a stable prefrontal cortex would, ideally, be able to think rationally and have the mental fortitude to fight off their cravings.

Although the treatment has worked on both rodents and humans (rats and people lost their cravings for cocaine after receiving it), it has not yet been tested on a large scale.

“It will take large, placebo-controlled trials to prove that the treatment works and the benefits last,” Smith explains in the article, however noting that, “The team plans to conduct further studies…testing brain stimulation to help people stop smoking, drinking, gambling, binge-eating and misusing opioids.”

Detox and Rehab: The First Steps Toward Recovery

While we may still be waiting for research that enables us to cure addiction for good, there are plenty of steps that individuals can take to help themselves today. If you or someone you know is struggling with a drug habit, it could be time to seek treatment.

At AspenRidge Recovery, our staff of medical professionals, therapists and addiction specialists can offer the support you need to get clean. If you’d like to speak with a member of our staff about potential treatment options, please don’t hesitate to call us today. We’re excited to help you get on the path to a happier, healthier life.

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