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Understanding How Opioids Affect the Brain

A man in distress, arms clasped over his head, deep in thought, illustrating the mental struggle linked to how opioids affect the brain.

It is no secret that the opioid epidemic is having a major impact across the country. More than 75 percent of the nearly 107,000 drug overdose deaths in 2021 involved an opioid. While the number of opioid prescriptions dispensed has been decreasing, illicit opioid use like fentanyl has been on the rise. 

With the variety of opioids available both legally and illegally, it is important to understand how opioids affect the brain. Recognizing warning signs associated with opioids makes it easier to identify when even legal use has become an issue for you or someone you love. 

Learning How the Brain Works 

To appreciate how opioids affect the brain, it is essential that we understand the basic functions of the brain. 

Our brains are made of approximately 86 billion neurons, or nerve cells, that send and receive messages throughout our bodies. These messages are sent through nearly 100 trillion connections that control everything we think, feel, and do. 

The messages in our brains come from neurotransmitters, or chemicals, that move from neuron to neuron. These chemicals travel through small gaps between neurons called synapses and attached to receptors, or receivers, on the neuron ends. Neurotransmitters are released in response to a variety of situations, such as movement, digestion, or stress. 

An illustration depicting two neurons connected by a synapse, labeled to showcase the fundamental structure of neuron communication. The larger circle magnifies the synapse area, illustrating the exchange with receptors and neurotransmitters. This diagram is used to show the neuronal pathways and processes and can provide an understanding on how opioids affect the brain.

The Brain’s Response to Pain 

One of the situations that triggers a response from your brain is pain. Whether you stub your toe or break your wrist, your brain recognizes pain and releases chemicals to help relieve it. 

These chemicals are known as endorphins, the body and brain’s natural painkillers. The word “endorphin” comes from the phrase “endogenous morphine.” “Endogenous” means it is created in the body, and “morphine” means it mimics the effects of that opioid. 

As your brain releases endorphins, they attach to receptors in your brain’s reward center, causing another chemical – dopamine – to be released. Dopamine is responsible for creating feelings of euphoria, which can be powerful for pain relief. 

How Opioids Affect the Brain 

Opioids may be naturally derived from poppy plants, such as morphine, or synthetically formulated in a lab, like fentanyl. However, they all offer temporary pain relief by mimicking the endorphins our bodies naturally produce. 

When opioids enter the brain, they attach to the same receptors as natural endorphins, providing the same pain relief experience. At the same time, opioids trigger the ventral tegmental area (VTA) of your brain’s reward system. This area releases dopamine to the nucleus accumbens (NAc), causing feelings of intense pleasure and satisfaction. 

An illustration of a human brain, highlighting the nucleus accumbens (NAc) and the ventral tegmental area (VTA), both areas that are affected by opioid use and how opioids affect the brain.

This overwhelming sense of euphoria is greater than our bodies’ natural response to pain. Over time, this causes our brain to favor opioid use and reduce endorphin production. This disruption in our brains’ normal communication can lead to increased sensitivity to pain and dependence on opioids. 

Although how opioids affect the brain is similar across different types of opioids, there are some key differences. These short- and long-term effects on the brain can influence how addiction develops and what recovery looks like: 


Morphine, one of the most prevalent drugs for treating severe pain, has a significant impact on the brain’s VTA. Because it strongly activates the release of dopamine, morphine creates feelings of euphoria that reinforce drug use. This effect makes it a highly addictive substance that requires careful monitoring when prescribing. 


Oxycodone, a semi-synthetic opioid, is commonly prescribed for moderate to severe pain, typically from surgical procedures. While it is similar to morphine, oxycodone works faster on the brain. Repeated use can alter brain activity and increase tolerance, leading to severe withdrawal, physical dependence, and repeated relapse. 


Hydrocodone is another semi-synthetic opioid that has a high potential for misuse and addiction. It is often prescribed for severe chronic pain that cannot be treated by other alternatives to opioids. This increases the probability of consistent, long-term use, so people taking hydrocodone may be prone to tolerance, dependence, and addiction.  


Heroin, which is processed from morphine, is a rapidly acting opioid. Upon entering the brain, heroin quickly binds to opioid receptors, leading to a fast intense high, like a rush. However, once the initial effects subside, people who use it can experience dangerously slow breathing. As a result, heroin use may lead to coma and permanent brain damage. 


Fentanyl is a synthetic opioid that, when made illegally, can be 50 to 100 times more potent than morphine. In addition to being stronger than other opioids, fentanyl is so risky because it is often added to other drugs. This is done without people knowing, which increases potential for the adverse and life-threatening effects of an overdose.

A woman with a distressed expression, her hands pressing against her temples, embodying the struggle of how opioids affect the brain.

Effects of Opioids on the Brain 

While opioids can serve as an important tool for managing pain, they can also significantly alter brain function. It is important to understand how opioids affect the brain, including short- and long-term effects such as: 

Short-Term Effects of Opioids

Long-Term Effects of Opioids

Seeking Treatment at BAART Programs 

Our specialized addiction treatment staff at BAART Programs recognize that opioids have physical, mental, and emotional effects on the brain and body. That is why we provide medication-assisted treatment, counseling sessions, and support services to address every aspect of your life. We are here to provide you compassionate care in a respectful environment so you can focus on success in recovery. 

If you or a loved one is dealing with opioid addiction, we can help you navigate the journey to recovery. We are here to guide you every step of the way, so contact us today or find your treatment center

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