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How Substance Abuse Affects the Brain

Substance abuse affects all parts of the body, including the brain. The chemicals found in substances such as opioids, alcohol, and stimulants can each affect the brain differently, and long-term addiction can have severe consequences on our physical and mental health if we do not choose to change our approach to life.

How Do Drugs Interact with the Brain?

Over time, people may use drugs or alcohol to escape uncomfortable feelings. Addictive substances interfere with neurons and neurotransmitters in the brain. Some, such as heroin, can interact with neurons because their chemical structure is similar to a substance naturally produced in the body, allowing the drug to interact with the same neurons. 


Other drugs, like cocaine, cause neurons to emit excessive amounts of natural neurotransmitters, disrupting the communication between neurotransmitters. Over time, the brain becomes less sensitive to natural neurotransmitters, instead relying on harmful substances to achieve the same feelings as before. 


Different areas of the brain are affected differently by substance abuse. The amygdala - the area of the brain responsible for feelings such as anxiety and unease - is significantly affected and becomes much more sensitive due to extended substance abuse. 


The prefrontal cortex of the brain is responsible for planning and self-control. It is the last part of the brain to mature, making teenagers and young adults more susceptible to damage due to substance abuse. Drugs and alcohol affect the prefrontal cortex and reduce impulse control, causing people to compulsively seek out substances. 

Addiction and Reward

The brain regulates almost everything we do, including experiences of pleasure. When not under the influence of drugs or alcohol, the brain releases feel-good chemicals such as dopamine as part of the reward system. For example, small acts such as cleaning, shopping, or finishing a big task can stimulate dopamine production in the brain. 


However, drugs and alcohol can affect the reward system of the brain. Substances such as cocaine and alcohol can also produce rushes of dopamine, resulting in pleasurable feelings and euphoria. These highs can be intense, and without them, the natural dopamine production in the brain falls dramatically. 


This leads people to continue taking substances to feel normal. As a result, the brain continues to reward harmful behavior, making it highly challenging for people to stop using. 


When people do stop taking addictive substances, it leads to withdrawal. The symptoms of withdrawal are intense and can include:


  • Tremors

  • Chills 

  • Fatigue

  • Irritability 

  • Nausea

  • Restlessness 


Withdrawal is caused because the brain is used to certain levels of neurotransmitters. Abruptly stopping taking a substance throws the brain and body off balance and is potentially dangerous if done without medical supervision. 

Can Drugs and Alcohol Damage the Brain?

Different drugs can have different damaging effects on the brain, including brain damage. Substances that can cause neurological damage include:


  • Alcohol

  • Heroin and opioids

  • Cocaine 

  • Amphetamines 


Amphetamines and alcohol disrupt something called the blood-brain barrier, which increases the permeability of brain cells. Greater permeability means more toxins from the blood supply can enter the brain.


Alcohol and inhalants can also damage the protective sheaths around nerve endings. Damaged nerve endings can affect thinking, vision, hearing, and movement, and depending on the severity of drug abuse, they can be serious. 

Recovery and the Brain

The brain is incredibly vulnerable to addiction but also remarkably resilient and can recover. Many studies have focused on how the brain can bounce back, with one finding that people who abused methamphetamine had lower numbers of dopamine proteins. However, after twelve months of recovery, the dopamine proteins were found to have increased by as much as 19%, suggesting that the brain can begin to heal itself after substance abuse.


The brain can recover more effectively from substance abuse with certain interventions. One study found that those who incorporated mindfulness and meditation into treatment had a reduced risk of relapse. It indicated that certain brain pathways that could potentially trigger relapse could be retrained by mindfulness. 


Recovery is a long process, and the brain will not change overnight; however, it is capable of change, even though it might be a challenge. The longer a substance is abused, the more ingrained it becomes in the brain. With hard work and support, these pathways can be altered and begin to pave the way to a healthier life.

Sustaining Recovery

Recovery does not end after detox or treatment. Recovery is a conscious choice every day, but many external factors can hinder it. The process involves finding the ideal environment for individuals struggling with substance abuse to continue their journey to long-term recovery, with safe, sober accommodation and access to supportive treatment, 12-step groups, and peer supports,

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