Heroin is an opiate that is derived from an opium, poppy. However, it remains a synthetic substance, so it has its own effects on the body because of this, which are more severe than more naturally derived substances.

Even though the substance was a prescription painkiller in the past due to its sedating effects on the CNS (Central Nervous System), the drug was later outlawed in the 20th Century, since it is highly addictive. In fact, the drug is still classified as a Schedule I drug, according to data from the CSA (Controlled Substances Act) and DEA (Drug Enforcement Agency).

Heroin still remains a substance, and its consumption will definitely affect major organ systems within your body – including your brain. Other than addiction, which is the most obvious effect, there are other ways that the drug harms the brain.

Long and short term effects

Many users consume the drug through injection, even though you can also snort it. The effects will begin to appear from a few minutes to an hour, depending on the method you used to consume it. The full effects of a dose, on the other hand, can last for up to several hours, although the initial rush (‘high’) of the drug lasts for a few minutes.

When the initial high wears off, you will find the user ‘nodding off’, or falling in and out of consciousness. Other short term effects are constipation, respiratory depression, flushing of the skin (due to irritation), loss of appetite, severe itching, dry mouth, mood swings and heavy extremities in emotional reactions.

All drugs are difficult to quit but heroin is even more so. Many people that struggle with addictions to heroin do so for several years, or even more. that leads to long term consequences of heroin abuse, which include overdoses, blood clots because of frequent injections, collapsed veins (again, due to injection), stroke, liver and kidney problems, lung infections such as pneumonia, and viral infections such as Hepatitis and HIV (due to sharing needles). For more on this, click here.

How does heroin use affect the brain?

The effects of heroin on the brain were not understood completely – at least until 1972. A research team from Johns Hopkins University revealed that the brain contains specific protein receptor sites for opiates. These includes morphine, codeine, opium, and heroin itself. Heroin is capable of causing damage to your brain in several ways.

It changes the reward system in the brain, through changing the levels of dopamine in the nervous system. The initial levels of the substance causes the flooding of the body with the opioid, and this leads to the brain producing dangerously high levels of dopamine. In fact, the dopamine levels that flood the body after that initial surge might be up to ten times the natural levels of the body.

When the substance enters the brain, the enzymes will convert it to morphine, and this will bind to the opioid receptors in the brain. That binding leads to changes in pain perception and even euphoria – which is why heroin is considered very addictive. These sensations are more intense than you think – even more powerful than the natural endorphins the body releases on a usual basis.

Breathing depression

Opioids do not just function as sources of pain regulation – they also act as a control center for breathing. People who abuse heroin go through depressed breathing, regardless of whether they have overdosed on the drug or not.

Depressed breathing, to put it simply, is when the breathing rate becomes shallow, irregular or slow, making the body receive lesser amounts of oxygen. Since the oxygen levels are reducing, the brain starts to reduce the functioning of other body systems, such as the circulatory and excretion systems, and that can result in organ failure as well as brain damage.


This builds up after the continual use of substances in general. After you are exposed to opioid drugs as well as the increasing levels of dopamine, the brain gradually lowers its pain thresholds – meaning your overall sensitivity to pain is increased,

The cause of this is unclear, but it is suggested that frequent doses of heroin lead to over activity of pain signal pathways. This makes the user want more amounts of the drug in order to ‘feel normal’, and that will establish a tolerance that makes you use increasing amounts of the drug each time. 

Long term effects

The long term use of the substance begins to have effects on the areas of the brain that are associated with decision making, long-term memory, social behavior and complex thinking. These are mainly the medial temporal lobe and the prefrontal complex.

Behavioral changes will result, including reduced memory, poor ability to regulate your emotions, reduced ability to be flexible with tasks, reduced skills in reasoning, poor ability to make choices, and lowered ability to plan and imagine future scenarios.

There is even evidence that shows the increasing cases of brain damage due to heroin that result in conditions similar to dementia and Alzheimer’s. This is due to increasing levels of inflammation in the brain as well as a buildup of proteins.

Can the damage be treated or reversed?

The best mode of treatment for any damages to the brain from heroin use is through detox and entering a rehabilitation program. When you remove the main cause of the addiction, the body might recover some of its functions spontaneously, while others are likely to take more time. Those that cannot heal from detox are treated through other medical techniques.

However, in all of this, do not attempt to detox from heroin by yourself – this can lead to death. Instead, medical supervision is best, as you get some drugs to wean the body off the drug. A medical professional will work with you to find the best dose to give, until the body is at a safe level of not requiring the drug to function.

Final thoughts

Heroin has several effects on your health, but also has effects on the brain. It is highly addictive, and its long lasting damage is highly fatal – but through detox and rehabilitation, the body is able to recover and you can live a healthy life.