How Does Heroin Affect the Brain?


Heroin is derived from the seed pod of the opium poppy. The drug is often perceived as belonging to the lower classes and specific demographics, but this is not true. 

It is abused by everyone, no matter what class they identify with. The National Institute on Drug Abuse estimates that there were nearly 948,000 Americans that used heroin in 2016.

Like most substances, heroin affects major organs but especially the brain. 

What Is Heroin?

Heroin is a drug that affects the brain, and most importantly, the mind. Heroin slows down breathing and heart rate, leading to death from overdose if not treated quickly enough. 

It also affects the parts of the brain responsible for judgment and decision-making, leading to being led astray by several different drugs, including alcohol and cocaine. 

It is commonly abused by injecting it intravenously, inhaling it as a powder, and smoking it. All three methods quickly cross the blood-brain barrier.

Heroin is converted back into morphine upon entering the brain and binds to opioid receptors throughout the central nervous system and the body. 

Opioid receptors govern pain perception and reward, so heroin decreases pain and increases pleasure.  

Signs and Symptoms of Heroin Addiction 

Signs and symptoms of heroin abuse will vary from person to person. Length of abuse and mental illnesses will also affect symptoms of individuals. Some of the most common signs and symptoms of heroin abuse addiction:


  • Flushed skin 
  • Euphoric rush 
  • Nausea and vomiting 
  • Slowed heart rate 
  • Severe itching 
  • Drowsiness for hours 
  • Clouded thinking 
  • Heaviness of limbs
  • Small pupils 
  • Watery eyes
  • Runny nose
  • Itching skin
  • Drowsy or relaxed


  • Owning drug paraphernalia 
  • Losing valuables or money 
  • Legal trouble 
  • Lying and secretiveness 
  • Intermittent heroin use, also known as chipping 
  • Track marks  

Heroin and the Brain

The alterations that heroin causes to the brain are both structural and chemical. Structurally, the brain will start to shrink as connections between neurons are lost. 

This shrinking is reversible if a person stops using heroin, but it can cause some permanent damage. The chemical changes that heroin causes to the brain are even more concerning. 

The drug alters how the brain produces and uses neurotransmitters, chemicals that allow communication between neurons. 

This can lead to mood, thinking, and motivation problems that can be very difficult to treat.

The chemical makeup of heroin indeed destroys the brain’s fundamental functions. Heroin directly works on the neural centers responsible for the two most important motivators; reward and punishment.

The more a person abuses heroin, the more their brain is altered structurally and chemically so that eventually, they have trouble thinking about anything else but getting high.

When heroin enters the brain, it turns into morphine and binds to proteins called opioid receptors. 

These proteins are located in many areas of the brain responsible for feelings like pain, happiness, need, satisfaction, pleasure, and reward.

The effect of heroin on the brain is swift and intense and can last 3-5 hours.

Withdrawal Symptoms 

When individuals are addicted to heroin, they become physically dependent on the substance prompting them to be afraid of being without it. This is especially hard when they attempt to get treatment for their substance abuse. 

Heroin withdrawal symptoms can start as soon as a few hours after sustained use. Withdrawal symptoms can include:    

  • Intense cravings 
  • Fever 
  • Runny nose 
  • Fatigue 
  • Muscle and body aches 
  • Cold sweats 
  • Diarrhea 
  • Insomnia
  • And more 

Withdrawal symptoms can cause serious medical complications, so it’s essential to contact a mental health professional before attempting to detox. 

Brain Damage from Heroin Use

There are many complications that heroin abuse can cause. Firstly heroin addiction completely rewires the brain. It makes changes to the brain’s reward system, making it not function properly and causing addiction. 

Further, opioid receptors in the brain are associated with pain relief and breathing. The breathing of someone who abuses heroin, even at non-overdose levels, will be depressed. 

It occurs when the breathing becomes shallow, slow, or irregular, which results in the body receiving less oxygen. By using less oxygen, the brain will begin to affect other systems in the body, resulting in organ damage. Brain damage may also result from insufficient oxygen intake.

Get Help With SoCal Sunrise Today

Withdrawal symptoms can cause serious medical complications, so it’s essential to contact a mental health professional before attempting to detox.  

If you or a loved one needs help with their heroin addiction, contact us today. We provide personalized heroin detox and rehabilitation.  

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