After your nervous system is consistently exposed to opioids and the subsequent elevated levels of dopamine, you adjust and develop a tolerance to heroin.

How heroin affects the nervous system is important to understand because it reveals how heroin can create the effects it does, such as the euphoric high, but it also highlights why this is such a dangerous drug.

The nervous system is the network of nerves and cells responsible for the delivery of messages between the brain, the spinal cord and the rest of the body. The central nervous system includes the brain and spinal cord.

There are two key areas to look at when addressing how heroin affects the nervous system. The first is the immediate effects on the brain, including the nervous system, and the second is the long-term impact the drug can have on the brain and nervous system.

What Happens When You Take Heroin

How heroin affects the nervous system is also how it’s responsible for creating the pleasurable high people chase when they take the drug.

Heroin is an opioid, like many prescription drugs that are abused. When someone takes an opioid like heroin, it first affects the nervous system by binding to opioid receptors. When this happens, there is a flood of dopamine that rushes into the person’s system and that’s what’s responsible for the euphoric high.

When opioids bind to these specific receptor sites in the brain they also control how the body perceives pain, which is why opioids are used as prescription pain medicines.

The levels of dopamine that are introduced to the body with the use of heroin are much higher than what would happen naturally. In fact, there are estimates showing the level of dopamine that flood the body with heroin may be up to ten times the amount that’s naturally produced by the body in situations involving pleasure or pain relief.

That anomaly means the sensations are much more elevated than what you could experience if your body’s natural endorphins were to bind to opioid receptors.

How Heroin Affects the Nervous System and Brain

The key areas of the brain that are impacted by heroin are related to the reward or pleasure pathways and they include the frontal cortex and the nucleus accumbens. These circuits are important for natural rewards such as what comes when you enjoy a meal or have sex. So if you were to do something pleasurable, such as eat, your dopamine level would increase. However, with heroin, the dopamine increases are significantly amplified and it also changes your brain’s reward pathways.

After your nervous system is consistently exposed to opioids and the subsequent elevated levels of dopamine, you adjust and develop a tolerance to heroin. This adjustment means that your threshold for pain is lowered, and your sensitivity to pain is higher. Some of these side effects may even begin as soon as after the first time you use the drug.

After you begin using heroin, your pathways that signal pain become overactive, and in this way, heroin affects the nervous system by creating the feeling that you need to keep using heroin to maintain a sense of normalcy.

Another way that heroin affects the nervous system is the fact that it depresses activity. This occurrence means it slows down vital functions of the brain and the entire nervous system, including respiration. This is what causes people to overdose from heroin.

How heroin affects the nervous system as a depressant also includes the fact that it can cause an irregular heart rate, and it can lower their body’s temperature and blood pressure.

How Heroin Affects the Nervous System in the Long-Term

So, the ways that heroin affects the nervous system can happen relatively quickly, but what about how heroin affects the nervous system in the long-term?

First, when you are a long-term user of heroin, it begins to affect two key areas of the brain: the prefrontal cortex and the medial temporal lobe. These are areas that are responsible for controlling memory, decision-making, self-control of social behavior and complex thought.

Over time as you use heroin, it impacts your central nervous system which can lead to problems with rational thinking, memory, impulse control and judgment.

How heroin affects the brain in the long-term can include reduced executive functioning, including impaired reasoning and problem-solving, as well as an inability to make decisions or plan for the future. People who abuse heroin may also have problems with emotional processing. The longer and heavier the abuse of heroin, the more the brain rewires itself in a way so that functioning without the drug becomes increasingly difficult. Over time it also becomes harder and harder to make decisions, show judgment and experience pleasure naturally without the use of drugs.

Both the short-term and long-term ways that heroin affects the nervous system can diminish the health and well-being of the person abusing the drug, as well as negatively impacting the people close to them.

a man with a beard wearing glasses and a hoodie.
Editor – Thomas Christiansen
With over a decade of content experience, Tom produces and edits research articles, news and blog posts produced for Advanced Recovery Systems. Read more
Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.