The Effects of Drug Addiction on the Brain and Body

Drug addiction is a treatable, chronic medical disease that involves complex interactions between a person’s environment, brain circuits, genetics, and life experiences.

People with drug addictions continue to compulsively use drugs despite the negative effects.

Substance abuse has many potential consequences, including overdose and even death. Learn about the short and long-term effects of drug addiction. Discover treatment options for common symptoms.

Treatment for Drug Addiction - Illustration by Theresa Chiechi

Verywell / Theresa Chiechi

Short-Term Effects

People can become addicted to any psychoactive ("mind-altering") substance. Common addictive substances include alcohol, tobacco (nicotine), stimulants, hallucinogens, and opioid painkillers.

Many of the effects of drug addiction are similar, no matter what substance someone uses. The following are some of the most common short-term effects of drug addiction.

Physical Effects

Drugs can produce many short-term physical effects. These may include:

  • Shallow breathing
  • Elevated body temperature
  • Rapid heart rate
  • Increased blood pressure
  • Insomnia
  • Drowsiness
  • Slurred speech
  • Decreased or increased appetite
  • Uncoordinated movements

Drug abuse can also lead to dependence and withdrawal symptoms, even in the short-term:

  • Dependence: People can become physically dependent on a substance fairly quickly. This means they need a larger amount of that substance to get the same “high.”
  • Withdrawal symptoms: When someone with a dependence on a drug stops using it, they can experience withdrawal symptoms, such as excessive sweating, tremors, panic, difficulty breathing, fatigue, irritability, and flu-like symptoms.

Drug Abuse vs. Drug Addiction

While the terms “drug abuse” and “drug addiction” are often used interchangeably, they're different.  Someone who abuses drugs uses a substance too much, too frequently, or in otherwise unhealthy ways. However, they ultimately have control over their substance use.

Meanwhile, someone with a drug addiction abuses drugs in a way that affects every part of their life. They can't stop misusing drugs even if they want to.

Mental Effects

Psychoactive substances affect the parts of the brain that involve reward, pleasure, and risk. They produce a sense of euphoria and well-being by flooding the brain with dopamine.

This leads people to compulsively use drugs in search of another euphoric “high.” The consequences of these neurological changes can be either temporary or permanent. 

The short-term mental effects of drug abuse can include:

  • Difficulty concentrating
  • Irritability 
  • Aggression
  • Angry outbursts
  • Lack of inhibition 
  • Hallucinations

Long-Term Effects

If drug addiction is left untreated, it can lead to a range of serious long-term effects. These are some of the most common long-term effects of drug addiction on the brain and body.

Physical Effects

Drug addiction can have serious long-term physical consequences, including major organ damage and even death.

Some of the most common long-term physical effects of drug addiction include:

Overdose Deaths in the United States

According to the Centers for Disease Control and Prevention (CDC), over 100,000 people in the U.S. died from a drug overdose in 2021.

Mental Effects

When someone continues to use drugs, their health can deteriorate both psychologically and neurologically. Some of the most common long-term mental effects of drug addiction are:

Signs of Drug Addiction

The signs of drug abuse and addiction include changes in behavior, personality, and physical appearance.

If you’re concerned about a loved one’s substance use, here are some of the red flags to watch out for:

  • Changes in school or work performance
  • Secretiveness 
  • Relationship problems
  • Risk-taking behavior
  • Legal problems
  • Aggression 
  • Mood swings
  • Changes in hobbies or friends
  • Sudden weight loss or gain
  • Unexplained smells on the body or clothing

Drug Addiction in Men and Women

Men and women are equally likely to develop drug addictions. However, men are likelier than women to use illicit drugs, die from a drug overdose, and visit an emergency room for addiction-related health reasons. Meanwhile, women are more susceptible to intense cravings and repeated relapse.


While there's no single “cure” for drug addiction, it's about as treatable as other chronic diseases. The primary ways of treating drug addiction include:

  • Psychotherapy: Psychotherapy, such as cognitive behavioral therapy (CBT) or family therapy, can help someone with a drug addiction develop healthier ways of thinking and behaving.
  • Behavioral therapy: Common behavioral therapies for drug addiction include motivational enhancement therapy (MET) and contingency management (CM). These therapy approaches build coping skills and provide positive reinforcement.
  • Medication: Certain prescribed medications help to ease withdrawal symptoms. Some examples are naltrexone (for alcohol), bupropion (for nicotine), and methadone (for opioids).
  • Hospitalization: Some people with drug addiction might need to be hospitalized to detox from a substance before beginning long-term treatment.
  • Support groups: Peer support and self-help groups, such as 12-step programs like Alcoholics Anonymous, can help people with drug addictions find support, resources, and accountability.

There are many different ways of treating drug addiction. Forming an individualized treatment plan with the help of your healthcare provider is likely to be the most effective approach.


Drug addiction is a complex, chronic medical disease that causes someone to compulsively use psychoactive substances despite the negative consequences.

Some of the short-term effects of drug abuse and addiction include changes in appetite, movement, speech, mood, and cognitive function. The long-term effects can include major organ damage, cognitive decline, memory loss, overdose, and death.

Treatment for drug addiction may involve psychotherapy, medication, hospitalization, support groups, or a combination.

Related: Relapse After Recovery

Seek Help

If you or someone you know is experiencing substance abuse or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357.

A Word From Verywell

If you're experiencing drug addiction, you’re not alone. Drug addiction is common, but it's also preventable and treatable. The earlier you seek help and inform yourself about the effects of drug addiction, the faster you can achieve long-term recovery.

Frequently Asked Questions

  • Can you fully recover from drug addiction?

    There's no “cure” for drug addiction. However, treatment for drug addiction is about as successful as a treatment for other chronic diseases. A combination of medication and behavioral therapy has been found to have the highest success rates in preventing relapse and promoting recovery.

  • How can you help someone with drug addiction?

    If you suspect that a loved one is experiencing drug addiction, address your concerns honestly, non-confrontationally, and without judgment. Focus on building trust and maintaining an open line of communication while setting healthy boundaries to keep yourself and others safe. If you need help, contact the SAMHSA National Helpline at 1-800-662-4357.

  • What are the most common signs of drug addiction?

    The most common signs of drug addiction include physical, behavioral, and mental changes. Physical signs of drug addiction may include:

    • Exhaustion
    • Slurred speech
    • Weight loss or gain
    • Bloodshot eyes,
    • Unexplained changes in physical appearance

    Behavioral changes can include:

    • Poor performance at work or school
    • Relationship problems
    • Risk-taking and reckless behavior
    • Illegal behavior
    • Secretiveness and dishonesty
    • Loss of interest in friends or hobbies

    Mental and emotional changes can include:

    • Irritability
    • Hyperactivity
    • Lack of motivation
    • Anger
    • Sadness
    • Anxiety
    • Paranoia
12 Sources
Verywell Health 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.
  1. American Society of Addiction Medicine. Definition of addiction.

  2. Cleveland Clinic. Drug addiction.

  3. American Addiction Centers. Get the facts on substance abuse.

  4. Bradford Health Services. Substance abuse vs. substance addiction.

  5. National Institute on Drug Abuse. Understanding drug use and addiction.

  6. Footprints to Recovery. The health risks of drug addiction.

  7. Centers for Disease Control and Prevention. Drug overdose deaths in the U.S. top 100,000 annually.

  8. American Psychological Association. Cognition is central to drug addiction.

  9. Tennessee Department of Mental Health & Substance Abuse Services. Warning signs of drug abuse.

  10. National Institute on Drug Abuse. Sex and gender differences in substance use.

  11. National Institute on Drug Abuse. Treatment and recovery.

  12. Grella CE, Stein JA. Remission from substance dependence: differences between individuals in a general population longitudinal survey who do and do not seek help.Drug and Alcohol Dependence. 2013;133(1):146-153. doi:10.1016/j.drugalcdep.2013.05.019

By Laura Dorwart
Laura Dorwart is a health journalist with particular interests in mental health, pregnancy-related conditions, and disability rights. She has published work in VICE, SELF, The New York Times, The Guardian, The Week, HuffPost, BuzzFeed Reader, Catapult, Pacific Standard,, Insider,, TalkPoverty, and many other outlets.