What Is Drug Addiction?

Understanding patterns, causes, and treatment

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

People with drug addictions compulsively use psychoactive substances, such as alcohol, illicit drugs, or prescription drugs, despite negative consequences. 

Issues with substance use are common. About 18.7 million (1 in 12) adults in the United States will have a substance use disorder (SUD) in their lifetime.

Learn more about drug addiction, including signs, treatment, and how to cope.

A man and woman hug each other at a peer support group.

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What Is Drug Addiction?

The American Society of Addiction Medicine (ASAM) defines drug addiction as “a treatable, chronic medical disease involving complex interactions among brain circuits, genetics, the environment, and an individual’s life experiences.” 

People with drug addictions continue to use drugs compulsively despite the harmful consequences.

Drug addiction can lead to serious health consequences and even death. However, it's preventable and treatable. 

Some of the most common addictive substances include:


Drug addiction isn't an official diagnosis in the "Diagnostic and Statistical Manual of Mental Health Disorders, 5th Edition" (DSM-5). Instead, the DSM-5 refers to SUD.

SUD involves the unhealthy use of a drug and dependence, whether physical, emotional—or both.

The diagnostic criteria for SUD include various aspects of a person’s chronic misuse of substances and drug-seeking behavior. These factors include:

  • Amount: Using a higher amount of alcohol or drugs than intended
  • Control: Being unable to quit or cut back 
  • Time: Spending a lot of time looking for or using a substance
  • Cravings: An overwhelming desire for the substance
  • Obligations: Being unable to meet responsibilities at home, work, or school
  • Social: Continuing substance use despite its negative effects on relationships
  • Activities: Changing lifestyle, hobbies, and social events for the substance
  • Hazard: Putting one’s own safety or the safety of others at risk
  • Harm: Continuing substance use despite negative consequences
  • Tolerance: Needing more of the same substance to get the same effect over time
  • Withdrawal: Experiencing physical symptoms when not using the substance

Early Warning Signs

The early warning signs of drug addiction vary depending on the substance a person is using. However, they can include changes in behavior, mood, physical health, and appearance, for instance:

  • Behavior: Changes in hobbies, friends, relationships, or performance at school and work
  • Mood, emotions, and personality: Hyperactivity, irritability, anger, paranoia, or secrecy
  • Physical health and appearance: Insomnia, weight loss or gain, tremors, or fatigue 

Over time, the signs of drug addiction can become more obvious and serious. These could include: 

  • Legal problems
  • Risky behavior and accidents
  • Divorce and breakups
  • Financial troubles
  • Severe health problems
  • Potentially fatal overdose

If you’re worried about your own substance use or someone else’s, here are some of the warning signs to watch out for. 


According to the 2019 National Survey on Drug Use and Health (NSDUH), about 15 million people aged 12 and older had alcohol use disorder (AUD). 

Early warning signs of alcohol addiction include drinking alone or in secret, drinking to curb stress or relax, having bloodshot eyes, feeling hungover when not drinking, short-term memory loss, and drinking more often or more frequently.

Over time, alcohol can cause severe health problems, such as chronic liver disease (cirrhosis).


In 2015, about four million adults in the U.S. met the criteria for marijuana use disorder (MUD).

Signs of dependence on marijuana often involve withdrawal symptoms like restlessness, lowered appetite, irritability, and problems with sleep or mood that peak in the weeks after quitting.


Stimulants are drugs that increase the activity of the nervous system. They include prescription drugs for attention deficit hyperactivity disorder (ADHD) like Adderall and Ritalin, as well as illegal drugs like cocaine and methamphetamine. 

Signs of stimulant use disorder (SUD) include:

  • Hyperactivity
  • Irritability
  • Fast or irregular heartbeat
  • Racing thoughts, fast-paced speech
  • Tooth decay
  • Weight loss
  • Sexual dysfunction
  • Angry outbursts

Stimulant misuse and addiction can eventually lead to heart and lung damage, heart attacks, and stroke.


Hallucinogens alter users’ awareness of their surroundings and perception of reality.

They include drugs like MDMA (ecstasy or Molly), LSD, and psilocybin (mushrooms). 

Signs of hallucinogen use disorder (HUD) include:

  • Panic
  • Poor judgment
  • Poor focus
  • Aggression
  • Vision changes
  • Heightened spiritual experiences, amnesia
  • Disorientation

In some cases, hallucinogens can cause psychosis, difficulty breathing, seizures, and overdose.


The nicotine in tobacco products, including e-cigarettes and vapes, is highly addictive. Signs of tobacco use disorder (TUD) include withdrawal symptoms like irritability, anxiety, increased appetite, “brain fog,” and short-term memory issues. 

Nicotine addiction can eventually lead to health problems like lung cancer, heart damage, cognitive decline, and Alzheimer’s disease.


Opioid painkillers include illegal drugs like heroin and synthetic opioids like fentanyl, as well as prescription drugs like morphine, hydrocodone, codeine, and oxycodone.

Opioid addiction and overdose death rates have recently increased dramatically in the U.S In 2019, nearly 50,000 overdose deaths (about 70% of all overdose deaths) involved opioids. 

Early signs of opioid addiction can include:

  • Mood swings (especially between irritability and euphoria)
  • Multiple doctor visits to try to obtain prescriptions
  • Slurred speech
  • Hypersensitivity to pain
  • Impaired judgment
  • Changes in sleep or hygiene
  • Flu-like symptoms
  • Taking prescription opioids in ways that aren't prescribed


Inhalants are products like aerosol sprays, gases, and solvents. They’re often common household items, such as glue or spray paint, that can be used to get high. 

Signs of inhalant use disorder (IUD) include scabs or sores around the mouth, chemical smells on the body or clothes, unusual purchases or amounts of trash, uncoordinated movements, and slurred speech. Eventually, inhalant use can lead to brain damage, hearing loss, bone marrow damage, and kidney and liver damage.


There's no single cause of drug addiction. However, researchers have identified some of the reasons that people tend to start using drugs compulsively, such as:

  • Family history: You're more likely to develop a drug addiction if multiple members of your family also have addictions.
  • Genetics: About 40% -60% of drug addictions stem from genetic, or hereditary, factors.
  • Environment: Drug availability, peer pressure, loneliness, and other environmental factors can all play a role in drug addiction.
  • Changes in the brain: Most psychoactive substances change the way your brain processes risk, rewards, and pleasure. These changes can lead you to keep using drugs despite the obvious harm.

Is Drug Addiction Hereditary?

There's strong evidence from twin, family, and adoption studies for a genetic component to drug addiction. One review suggests that, out of a selection of the most common addictive substances, the heritability of cocaine addiction is highest.


The following risk factors put someone at a higher risk of developing a drug addiction:

  • Trauma: Experiencing trauma, such as domestic abuse or child abuse, puts someone at a greater risk of misusing substances. Post-traumatic stress disorder (PTSD) is highly comorbid with SUD.
  • Mental illness: Drug addiction is often co-occurring with other mental health conditions, such as anxiety, depression, mood disorders, schizophrenia, ADHD, and personality disorders. Some estimates suggest that about half of people with a mental illness experience a SUD during their lifetime.
  • Poverty: Factors like poverty, unemployment, food insecurity, and homelessness can put someone more at risk of developing a drug addiction. 
  • Early exposure: The earlier someone was exposed to alcohol or drugs, the likelier they're to develop a drug addiction later in life.


It’s hard to know how to help someone with drug addiction, including yourself. While there isn’t a “cure” for drug addiction, it can be treated effectively like many other chronic diseases. 

Here are some of the most common treatments for drug addiction: 

  • Psychotherapy: Psychotherapy – including cognitive behavioral therapy (CBT), family counseling, group therapy, contingency management (CM), motivational enhancement therapy (MET), and substance abuse counseling – can help you address your drug addiction as well as any underlying mental health conditions.
  • Medication: Medications can be prescribed to help with withdrawal and to treat symptoms of other mental illnesses, such as depression. Examples of commonly prescribed drugs for withdrawal management include methadone, naltrexone, and buprenorphine.
  • Support groups: Peer support and self-help groups, both online and in-person, can help you find ongoing support and resources as you navigate recovery. 
  • Hospitalization: Particularly if you're experiencing withdrawal symptoms, it might be necessary to be hospitalized to detox from a substance.

How to Cope

In addition to medical treatment, here are some of the ways you can help yourself or a loved one with drug addiction:

  • Educate yourself: It’s important to arm yourself with as much knowledge as possible about drug addiction, including its potential outcomes if left untreated. Informing yourself about the long-term effects of drug addiction can be a good first step toward recovery.
  • Improve coping and problem-solving skills: In many cases, people use substances as a way of coping with stress. Whether on your own or with a mental health professional, try to develop a toolbox of healthier coping skills so you don’t turn to drugs or alcohol when problems arise.
  • Grow your support system: Many people with drug addictions don't have a strong support system. Joining a recovery support group or getting involved in your community can help you stay accountable and build a stronger network of resources.

When to Talk to Your Healthcare Provider

If you think it might be time to talk to your healthcare provider about your substance use, ask yourself these questions:

  • Have you recently been using alcohol or drugs more frequently or in higher amounts than you want to?
  • Do you sometimes have a strong craving for alcohol or drugs?
  • Do you find yourself “losing time” or blacking out after using substances?
  • Do you use alcohol or drugs to cope with stress, such as relationship problems?
  • Do you ever find yourself involved in fights after using a substance?
  • Have family, friends, or colleagues noticed you behaving differently?
  • Do you feel irritable, depressed, or physically sick when you can’t use drugs?
  • Do you spend a lot of time or money while using or planning to use substances?
  • Do you ever avoid activities or miss out on important events because of your drug use?

Seek Help

If you or someone you know is dealing with substance abuse or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 (800-662-HELP). SAMHSA also provides an online treatment center location.

If you or someone you know are having suicidal thoughts, dial 988 to contact the 988 Suicide & Crisis Lifeline and connect with a trained counselor.


Drug addiction is a medical condition that causes someone to use alcohol and/or drugs compulsively despite negative consequences to their health, relationships, and well-being. Any psychoactive substance can be addictive. Addiction is caused by a complex interaction of factors, including genetics, environment, lifestyle, family history, co-occurring mental health conditions, stress, and trauma.

Over time, drug addiction can cause serious health issues, such as heart disease, certain cancers, organ damage, neurological problems, and potentially fatal overdose. Treatments for drug addiction include psychotherapy, medical detox, prescribed medication, and support groups.

A Word From Verywell

If you think you might have a drug addiction, you’re not alone. Addiction is common and treatable. It doesn’t need to be a source of stigma or shame. Educate yourself as much as possible and don’t be afraid to seek help if you need it.

Frequently Asked Questions

  • What does addiction feel like?

    Drug addiction affects the parts of the brain involved in reward, stress, pleasure, self-control, and risk.

    People who are addicted to alcohol or drugs might feel an overwhelming craving for a substance. They often feel preoccupied or even obsessed with using, obtaining, or planning to use a drug. People with drug addictions may also feel helpless to stop compulsively using a substance, even if they want to.

  • How addictive is sugar compared to drugs?

    Some research suggests that high-sugar foods act similarly on the areas of the brain that involve rewards and cravings.

    In experimental animal studies, rats became even more addicted to sugar than to cocaine. However, researchers don’t yet agree on whether sugar and drugs can be considered addictive in the same way.

  • Which drugs are illegal?

    Drug laws vary in the U.S. by state. To find out whether a drug is legal, it’s best to consult the United States Drug Enforcement Administration (DEA) as well as state, local, and federal laws. Some drugs are illegal for anyone to possess, while others are illegal to use if they’re not prescribed to you by a physician. Some examples of illegal drugs in the U.S. include cocaine, heroin, LSD, and fentanyl.

  • What are narcotic drugs?

    Many people used to refer to all psychoactive drugs as “narcotics” or “narcotic drugs.” Today, according to the DEA, “narcotics” specifically refers to opium, its derivatives, and its synthetic substitutes.

    These are more commonly known as opioids. Some examples of narcotic drugs are heroin, fentanyl, Vicodin, OxyContin, codeine, morphine, and methadone.

  • How can you help someone with addiction?

    To help someone with addiction, focus on building trust and communicating your concerns honestly without blaming, shaming, or judging. Make sure you also give the person privacy and maintain healthy boundaries for yourself to stay safe. For additional help, contact the SAMHSA National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

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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.
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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, Health.com, Insider, Forbes.com, TalkPoverty, and many other outlets.