Addiction’s Effect on the Brain

Our brains are essentially the leaders of our behavior. When a person has a substance use disorder or engages in harmful behavior repeatedly, it is not because they are weak or have no willpower. Addiction happens due to changes in the brain that create a lack of control over substances or activities, even when they cause harm. According to the National Center for Drug Abuse Statistics (NCDAS), more than 70% of people who have experimented with an illegal substance before the age of 13 have ended up with a substance use disorder.^[1] So, how does addiction affect the brain? Our brains consist of billions of nerve cells called neurons, which send messages or signals (called neurotransmitters) back and forth, allowing our bodies and minds to work the way they do. When substances are used or harmful behavior is engaged in, they disrupt communication processes, interfering negatively with how neurons send, receive, and process these signals.^[2][3]

How does addiction affect the brain’s reward system?

Take exercise as an example of a healthy activity. When we exercise, our brain releases feel-good hormones (like dopamine), which motivate us to want to exercise again or to engage in more healthy activities. If we observe addiction and the brain, the reward system works the same way, only more intensely.

When harmful substances or negative behaviors are introduced, the brain releases large amounts of dopamine. This results in a euphoric feeling or “high,” which is actually a change in brain chemistry, altering normal brain communication.^[4]

Some substances, such as heroin, act the same as certain brain chemicals, but they do not activate neurons in a natural way. Other drugs (like cocaine) can cause neurons to release too many natural neurotransmitters, also changing the way the brain communicates.^[5]

The strength of the “reward” determines the desire to use the substance or engage in the behavior again. Over time, the effect of the substance may become less intense or enjoyable because the brain has changed and adapted to the new messages it’s programmed to send and receive.

This ultimately causes a person to use more substance or engage in behavior more intensely to feel satisfied. This is what we refer to as tolerance. When a person becomes more tolerant of a substance, they need to use more to experience the same feelings.

When the substance wears off, withdrawal is experienced, which is a negative emotional state caused by the brain’s reward system, also decreasing its function. This can often result in physical illness, psychological changes, physical or mental stress, anxiety, and depression. These experiences could range from mild to unbearable, and more often than not, they lead the person to want more of what made them feel good to avoid feeling bad.^[6]

The Role of Neuroplasticity in Addiction

Neuroplasticity is when our nervous system changes or adapts to new experiences.^[7]

If we think of an addicted brain vs a normal brain, we can look at an example of how the brain responds to a healthy activity.

A person may want to create a new routine in their life, so they decide to wake up at 5 am every day and go for a walk in order to start the day on a positive note. The experience activates the reward system, leaving the person wanting it again. After repetition, it may begin to feel almost automatic, and the person may even feel like they didn’t have a great start to the day if they did not engage in this activity.

This is essentially how neuroplasticity works and how it affects those with substance use disorders. When harmful substances and behaviors activate the reward system of the brain, it trains the brain to want this experience again. With repeating the same experiences, the reward system acts automatically, creating an uncontrollably strong desire to need the substance.

The two general forms of neuroplasticity are defined as:

1. Tolerance with physical dependence: This occurs from repeating the action to feel the same reward, whether it be a substance or behavior. However, when it is stopped, the person craves more of the same thing just to feel good.
2. Compulsive behavior: Needing a substance as if it were a matter of survival that one cannot live without. This can be compared to behaviors that developed early in our evolution, such as seeking water or food.

The severity of the second form of neuroplasticity is that it is very stable and permanent, and individuals who develop this neuroplasticity from substances and harmful behavior have a higher risk of relapsing, even after abstaining for long periods.^[8]

Long-Term Effects of Addiction on Brain Function

Just like riding a bike, once you remove the training wheels and pedal down the road unassisted, your brain always remembers how to do it, no matter how long of a break you take from riding. The long-term effects of addiction are much the same; it is extremely difficult for the brain to forget about wanting or needing the substance or behavior. This is because the surge of neurotransmitters is greater than the amounts produced naturally from enjoyable experiences, like listening to music, socializing, or that early morning walk. It conditions the brain to want the substance or behavior instead of healthier activities. Additionally, simple situations in daily life could trigger the reflex to want a substance, even if the substance is not easily attainable or the person has strong intentions not to engage in the negative behavior.^[2] Over time, repeating harmful substances or behaviors can lead to structural and functional changes in areas of the brain that can be associated with emotion and memory. Other brain changes can cause issues like anxiety or depression and even learning problems.^[9]

Can recovery from addiction reverse negative effects on the brain?

Just as a scratch on our arm can heal with the right care, so too can the brain recover with proper treatment, either partially or fully from the effects of substance abuse or negative behaviors. Over time, some (and possibly all) of the long-term, detrimental effects of substance use can be improved.

With the right treatment, people who have suffered from substance abuse disorders or behavioral addictions can counteract the detrimental effects and go on to regain control over their lives. This is known as being in recovery.

Recovery is a long process where deep-seated neurological changes need to adapt to new behaviors, essentially becoming the new normal in the brain. Unfortunately for some, relapse is a reality of recovery. But relapse does not mean that recovery has failed. Treatments may just need to be modified.

Addiction affects the whole person, and because of this, a holistic approach to recovery must be taken. This may include mental, physical, and environmental considerations towards the correct treatment processes.^[10]

SAMHSA recently released new data on recovery in the US, stating that out of 29 million adults who perceived that they ever had a substance use problem, 72.2% (or 20.9 million) considered themselves to be in recovery or to have recovered from their drug or alcohol use problem.^[11]

If you have a substance use disorder or are addicted to harmful behaviors, know that there are treatments available, no matter how severe the situation. Talk to your medical practitioner about a treatment plan that will work for you.

Don’t feel despondent if the road to recovery is not easy. Know that there is always support available. It is possible to overcome this disease, and you do not have to walk the road alone.