Alcohol and Drugs: Their Damaging Effects on Your Brain

Exposing the many ways drug and alcohol abuse takes a terrible toll on our brains.

Frying eggs

If you’re old enough, you might remember the anti-drug ads of the 1980s: “This is your brain on drugs. Any questions?” Those words were accompanied by the image of an egg frying on a very hot cast-iron pan. That refrain was repeated for many years afterwards. How true was it? Are drugs harmful to the physical structure and function of the human brain? Fortunately, there is plenty of information available on this subject.

Drugs of Abuse and Their Effects

Alcohol: This is the drug that’s available in every state in the country. It’s legal to sell it to 21-year-olds almost everywhere in the U.S. Alcohol abuse at a young age can alter the development of the brain, resulting in lasting changes in its function.

Overdoses of alcohol cause some areas of the brain to shut down, resulting in depressed breathing function and slow heart rate. An overdose can also lead to permanent brain damage due to the destruction of brain cells. Alcohol overdoses are commonly called alcohol poisoning and can result in death. The person poisoned by alcohol may try to vomit but then inhale the vomited material, which then causes suffocation. Long-term alcohol abuse can cause a form of encephalopathy (brain disease) that results in the inability to control the movement of the eyes, poor coordination and balance, confusion, and dementia. If not treated early, the damage to the brain can become permanent.

Alcohol abuse among youth can have particularly damaging effects. Researchers have learned that heavy abuse of alcohol at a young age changes the connections between different parts of the brain. This can weaken areas involved in emotional and cognitive functioning. Early alcohol abuse can even bring about a reduction in the size of some parts of a young person’s developing brain.

tired man

Benzodiazepines: Changes to the brain after misusing benzodiazepines like Xanax or Valium can result in long-lasting symptoms like these:

  • Low energy
  • Memory loss
  • Difficulty focusing
  • Anxiety
  • Insomnia
  • Sensitivity to light and sounds
  • Body pain
  • Muscle weakness

These symptoms may last for years after misuse of benzodiazepines stops. Medical researchers have grouped these and other symptoms under one heading: benzodiazepine-induced neurological dysfunction or BIND.

Cannabis/Marijuana: When cannabis is used by a pregnant woman, studies indicate that their children could suffer from higher problems related to attention, memory, problem-solving skills, and behavior. Youth who use cannabis are likely to have poorer performance in school and more difficulty remembering[5]. One long-term study revealed that those who used cannabis over a long period of time had smaller hippocampi than those who did not. The hippocampus is a part of the brain associated with learning and memory.

brain scan on a screen

Cocaine: A recent study of the impact of cocaine addiction on the brain showed that those addicted to this drug had a reduced amount of gray matter in the brain. This gray matter forms the outer layer of the brain and is thought to control movement, memory, and emotions. Reduced gray matter appeared to result from an atrophy of these tissues. Cocaine-addicted individuals also had a higher brain age than non-users, based on each group’s performance on tests. Cocaine causes these effects because of its ability to cause inflammation, and its toxicity to nerve tissues.

Another possible type of brain injury resulting from cocaine use is ischemic stroke, a type of stroke resulting from oxygen being cut off from some part of the brain. One study found that young people who had used cocaine in the last 24 hours had a 6.4-fold risk of ischemic stroke.

Hallucinogens: It is well known that hallucinogens have a profound effect on the function of the brain, leading to hallucinations and changes in perceptions of colors, time, self, and thought processes. They may also have harmful effects on brain tissue itself. One study found that those who regularly used ayahuasca, a South American herb, experienced a thinning of the part of the brain associated with remembering the past and planning the future.

The powerful hallucinogen phencyclidine, or PCP, is known to have a directly damaging effect on the brain, including the potential for stroke.

Inhalants: Inhalant abuse involves the inhalation of any of hundreds of toxic household or industrial chemicals for the purpose of becoming intoxicated. Inhalant abuse can become addictive, and it can also be deadly, even the first time an inhalant is abused.

Effects of inhalant abuse include:

  • Dizziness
  • Slowed mental and physical functions
  • Blurred vision
  • Poor muscle control
  • Headache
  • Seizures
  • Coma
  • Involuntary and rapid movement of the eyes

Chronic use of these substances can result in encephalopathy or brain damage and disease.

Ketamine: Long-term abuse of this drug is associated with reduced volume of the gray matter of the brain. This can happen when brain cells die. Reduced volume of gray matter is associated with problems with language, focus, reasoning, and motor skills. The white matter that constitutes the inner part of the brain also loses its integrity. This part of the brain is essential for rapid exchange and communication between different parts of the brain. Also damaged is your brain’s connection with the thalamus which relays signals about your movements and senses to your brain. Poor communication between the thalamus and your brain can affect your sleep, consciousness, learning, and memory.

woman having a stroke from ecstasy use

MDMA: MDMA is better known as ecstasy or Molly. It is extremely common in nightclubs and dance venues, and at outdoor music festivals. In addition to creating euphoria, it creates dramatic changes to sensory messages. In the brain, it creates neurotoxins, or substances that are poisonous to brain and nervous system tissue. As it is a stimulant, an ischemic (lack of blood supply) stroke is more likely than a hemorrhage in the brain. Death of brain tissue can result from either strokes or neurotoxins.

Methamphetamine: Meth is a very powerful synthetic stimulant. It causes a fast increase in heart rate and blood pressure. These changes can be very hard on the brain. A not-possible result is a cerebral hemorrhage, a type of stroke resulting from bleeding in the brain. The risk of this type of hemorrhage is greater among methamphetamine users. Coma and death can result.

Opioids: Opioid drugs like heroin, morphine, fentanyl, oxycodone, and others depress breathing, which can mean the brain does not receive enough oxygen, resulting in a condition called hypoxia. When hypoxia is severe enough, death results. Hypoxia can also result in short- and long-term neurological effects, such as coma or permanent brain damage.

Cognitive, memory and motor impairments may result from opioid overdoses that are survived and can last for months. Symptoms of this damage include:

  • Amnesia
  • Loss of focus
  • Forgetfulness
  • Abnormal gait
  • Incontinence

Fentanyl, a synthetic opioid far more powerful than morphine or heroin, has been found to have particularly dangerous effects on the brain. Researchers found that fentanyl’s effect on the brain results in depression of the breathing far faster than it changes a person’s alertness. For that reason, fentanyl can cause nearly instant overdose deaths. The drug user may die before they are even aware of a problem.

Protect Your Brain; Avoid Drug Abuse

When people go bicycling, skateboarding, or engage in other active sports, most wear helmets to protect their heads, particularly their brains. Paradoxically, far too many people think nothing of loading up on alcohol, abusing benzodiazepines or cocaine, or using inhalants. They probably don’t know that they are risking everything, just like a person who goes through a car crash or other type of brain trauma. When a brain is permanently damaged, a person’s life may be changed forever.

Anyone who uses drugs is risking the function and health of their brain. If you or someone you care about is addicted, it’s vital to get help at the first minute possible to protect the health of the brain and life. The only safety is in sobriety.


  • “Alcohol and Brain Overview.” National Institute on Alcohol Abuse and Alcoholism, 2022. NIAAA
  • “Wernicke-Korsakoff Syndrome.” National Institute on Alcohol Abuse and Alcoholism, 2022. NIAAA
  • “Alcohol and the Adolescent Brain.” National Institute on Alcohol Abuse and Alcoholism, 2023. NIAAA
  • “Benzodiazepine Use Associated With Brain Injury, Job Loss and Suicide.” University of Colorado Anschutz Medical Campus. 2023. CU
  • Brain Health.” Centers for Disease Control and Prevention, 2020. CDC
  • “Cocaine Destroys Gray Matter Cells and Accelerates Brain Aging.” National Library of Medicine, 2023. NLM
  • “Cocaine Use and Risk of Ischemic Stroke in Young Adults.” National Library of Medicine, 2018. NLM
  • “Long-term Use of Psychedelic Drugs is Associated with Differences in Brain Structure and Personality in Humans.” National Library of Medicine, 2015. NLM
  • “Stroke Associated with Drug Abuse.” MedLink Neurology, 1996. Medlink
  • “Case Report: Toxic encephalopathy caused by repeated inhalation of toxic solvent.” National Library of Medicine, 2022. NLM
  • “Brain Changes Associated With Long-Term Ketamine Abuse, A Systematic Review.” National Library of Medicine, 2022. NLM
  • “MDMA and the Brain.” National Library of Medicine, 2020. NLM
  • “Clinical Characteristics and Outcomes of Methamphetamine-associated Intracerebral Hemorrhage.” National Library of Medicine, 2019, NLM
  • “What Are Prescription Opioids?” National Institute on Drug Abuse, 2021. NIDA
  • “Neurocognitive Impairments and Brain Abnormalities Resulting from Opioid-related Overdoses.” National Library of Medicine, 2021. NLM
  • “Study reveals fentanyl’s effects on the brain.” Harvard Gazette, 2022. Harvard Gazette


Karen Hadley

For more than a decade, Karen has been researching and writing about drug trafficking, drug abuse, addiction and recovery. She has also studied and written about policy issues related to drug treatment.