Brain Damage in People Who Use Heroin and Methadone

woman's hand holding heroin needle

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Drugs such as heroin and methadone can have a significant effect on the brain, particularly during important periods of development. These drugs also cause changes in brain circuits that are associated with pleasure, memory, learning, and decision-making, but they can have other damaging effects as well.

Drug Effects on the Brain

Some of the potential impacts of heroin and methadone use on the brain include:

  • Brain abnormalities
  • Changes in brain chemistry
  • Damage to brain cells
  • Decreased oxygen for brain tissue
  • Decreased task performance
  • Drug dependence and addiction
  • Memory impairment


In a 2005 study published in Neuropathology and Applied Neurobiology, researchers examined the brains of 34 people who used heroin and methadone who died at an average age of 26 years, some of which as young as age 17. Researchers compared their brains to the brains of 16 young people who also died young but who did not use drugs.

The examination found that people who used drugs were up to three times more likely to have brain damage than those who do not use drugs. The brains of those young people who used drugs appeared similar to those of much older people with the damage comparable to someone with Alzheimer's disease.

The damaged nerve cells were in the areas of the brain involved in learning, memory, and emotional well-being, and were similar to damage found in the early stages of Alzheimer's disease.

Other Drugs That Can Damage the Brain

While the 2005 study specifically looked at the effects of heroin and methadone use on the brain, several other drugs can lead to neurological problems as well, including:

  • Cocaine
  • Inhalants
  • LSD
  • Marijuana
  • MDMA
  • Mescaline
  • Methamphetamine
  • PCP
  • Prescription opioids

One important thing to note is that it is not just illicit drug use that can negatively affect the brain. Prescription drugs, including opioid pain relievers, can also cause brain damage.

Areas Affected

Drugs can affect the brain in a variety of ways, and the effects can vary depending on the type of drug used. Some of the brain areas that might be impacted include:

  • Amygdala: A part of the brain that plays a role in feelings of anxiety, fear, and stress that people often experience as part of drug withdrawal (People will often continue to use drugs or alcohol simply to avoid these unpleasant effects.)
  • Basal ganglia: An area of the brain critical in the motivation and habit formation and an important part of the brain's reward system (Drugs can diminish the sensitivity of the reward system, which makes it more difficult to experience pleasure without drugs.)
  • Prefrontal cortex: An area of the brain responsible for functions such as thinking, decision-making, planning, problem-solving, and self-control.

How It Happens

Heroin use leads to changes in the physical structure of the brain. These changes result in imbalances in neurons and hormones, which can be long-lasting and difficult to reverse.

Because drugs like heroin and methadone are depressants, they can cause decreased breathing and reduce oxygen levels in the blood and brain. In some cases, such as during a drug overdose, this can result in immediate effects that can potentially lead to death. It can also lead to cumulative effects that cause slower-to-develop damage to the brain. 

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

For more mental health resources, see our National Helpline Database.

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5 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. National Institute on Drug Abuse. Health consequences of drug misuse: neurological effects.

  3. National Institute on Drug Abuse. Drugs, brains, and behaviors: the science of addiction - drugs and the brain.

  4. National Institute on Drug Abuse. What are the long-term effects of heroin use?.

  5. U.S. National Library of Medicine. Cerebral hypoxia.