How Does Heroin Affect the Brain

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Heroin is an opiate that comes from the poppy plant but is a synthetic substance.

Once prescribed as a painkiller and legally available, heroin was prohibited at the start of the twentieth century due to its extremely addictive nature. Heroin remains a Schedule I controlled narcotic, according to the DEA (U.S. Drug Enforcement Administration). Schedule I drugs have no accepted medical use and a high potential for abuse and addiction. The effects triggered by heroin abuse can be damaging both physically and psychologically, particularly when addiction develops. Addiction to heroin is clinically classified as OUD (opioid use disorder). Like all addictions, OUD is a chronic brain condition characterized by relapse and the compulsive use of addictive substances regardless of negative outcomes.

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What Is Heroin?

Heroin is classified as a semi-synthetic opioid.   

Smoking, snorting, or injecting heroin prompts a near-instant rush of euphoria, while at the same time slowing down respiration and heart rate. 

A Schedule I controlled substance, heroin is powerfully addictive. Tolerance to this opioid develops rapidly. When tolerance forms, you will require more heroin or more frequent doses of heroin to achieve the same effects. 

As a CNS (central nervous system) depressant, heroin breaks down into various chemicals once ingested. These chemicals bind to the brain’s naturally occurring opioid receptors. Opioids like morphine and codeine have the same mechanism of action.

The sustained use of heroin will lead to heroin addiction (opioid use disorder) in almost all cases. 

Heroin enters the brain quickly, regardless of the route of administration. Once the substance enters the brain, it attaches to opioid receptors responsible for regulating these functions: 

  • Heart rate
  • Sleeping
  • Breathing
  • Pain
  • Pleasure

While using heroin can bring on some short-term complications, most adverse outcomes associated with this deadly opioid occur in the long-term. 

How does heroin affect the brain, then? 

An image of a man with his hands on his head, as he wonders how does heroin affect the brain

How Does Heroin Affect the Brain?

The brain has its own opioid receptors. These receptors create natural opiate chemicals as a response to pain. These opiates do not last for long, though, and they may not be strong enough to manage chronic pain. For this reason, the most powerful painkillers contain synthetic opioids as active ingredients. 

Although heroin is no longer legitimately used as a medicine, the substance nevertheless binds to the same opioid receptors. When the brain starts to encounter synthetic opioids, it is likely to produce less opiates. If this occurs, both the opioid receptors and the reward system in the brain are affected. This pathway uses dopamine, a neurotransmitter or chemical messenger. At the same time, the brain cuts back on the production of serotonin and dopamine due to their artificial release by heroin use.

Chronic heroin use leads to the development of tolerance and dependence. If you become dependent on heroin, extremely unpleasant withdrawal symptoms will manifest as the effects of the drug wear off. Symptoms include: 

  • Nausea
  • Vomiting
  • Chills
  • Aches
  • Exhaustion
  • Depression

Tolerance, Dependence, and Their Effects on the Brain

Many of the effects of heroin on the brain are indirectly triggered by tolerance and dependence. 

Repeated exposure to heroin causes tolerance to occur. As your body adjusts to a consistently increased dopamine level, so the effects of heroin are diminished. Continued use of heroin will accelerate the presentation of physical dependence. When you become dependent on heroin, your pain threshold will lower, resulting in increased sensitivity to pain. This can start happening after just a few uses of heroin. 

If you are dependent on heroin, the absence of this semi-synthetic opioid will trigger intense physical and emotional withdrawal symptoms. Addiction often closely follows. 

Can Heroin Abuse Cause Brain Damage?

Chronic heroin use can cause brain damage in various ways. 

Initially, using this drug long-term will prompt permanent changes to the brain’s reward system. When this occurs, functioning is compromised, and addiction develops.

Additionally, the opioid receptors in your brain are associated with pain relief and breathing. Abusing heroin can depress breathing dangerously, even at levels not high enough to trigger heroin overdose. When this happens, less oxygen is directed to the brain, slowing the functioning of other bodily systems. This can cause organ damage and brain damage.

Heroin abuse is also linked with a type of brain damage that resembles Alzheimer’s disease., potentially causing a form of dementia. Although these changes may be reversible, there is insufficient evidence to confirm this.

What Are the Longer-Term Mental Effects of Heroin Abuse?

Heroin addiction can damage your mental health by continuously exposing you to artificial dopamine highs. Over time, the brain alters its response to endorphins created naturally. This means that many people who use heroin do not seem to experience pleasure in everyday things. This condition – anhedonia – can persist even after physical dependence has been broken. 

Chronic heroin abuse can cause the following mental complications: 

  • Depression
  • Anxiety
  • Dramatic mood swings
  • Insomnia
  • Psychosis
  • Paranoia

While heroin addiction is an incurable brain condition, it responds favorably to treatment. We can help you with that at California Detox.

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Heroin Addiction Treatment at California Detox

If you require a supervised medical detox and inpatient or outpatient heroin addiction treatment, we can help you here at California Detox. We offer luxury rehab at affordable prices at all levels of intensity on the ASAM continuum of care

By engaging with a clinical detox, you can withdraw from heroin as comfortably and safely as possible. FDA-approved medications can ease the intensity of cravings for heroin and can also reduce the severity of withdrawal symptoms. After a week or so, you will be ready to transition into one of the following heroin addiction treatment programs: 

  • Inpatient program
  • Outpatient program
  • Virtual IOP (remote rehab via videoconferencing)
  • IOP (intensive outpatient program)
  • PHP (partial hospitalization program)
  • Dual diagnosis treatment program

All California Detox heroin addiction treatment program provide you with a personalized treatment plan drawing from these interventions: 

  • MAT (medication-assisted treatment)
  • Group counseling
  • Individual counseling
  • Psychotherapy (CBT and DBT)
  • Family therapy
  • Holistic therapy

When you are ready to commit to recovery from heroin addiction, we can help you from detox to discharge and beyond here at California Detox in Southern California. Call 949.390.5377 today and kickstart your recovery.


Yes. Heroin binds to opioid receptors in the brain, triggering the increased production of neurotransmitters like dopamine. This causes a profound sense of wellbeing and relaxation, as well as decreased sensitivity to pain.
Using heroin causes the artificial release of neurotransmitters like dopamine and serotonin. Resultantly, the brain will reduce its production of serotonin to compensate.


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