Why Do People Use Drugs? Reasons and Risk Factors

Published January 7, 2022 · Updated October 22, 2026

Medically reviewed by Danesh Alam MD, DFAPA, DFASAM

People usually start using drugs for one of four reasons: to feel good, to feel better, to do better, or out of curiosity and social pressure. That is how the National Institute on Drug Abuse (NIDA) sums it up. Whether use turns into addiction depends on many things, including genes, age at first use, childhood experiences, and mental health. Source: NIDA, Drug misuse and addiction.

Drug use is common. In 2025, 69.8 million people in the U.S. aged 12 or older, about 1 in 4, used an illicit drug in the past year. Marijuana was by far the most common. Source: SAMHSA, 2025 National Survey on Drug Use and Health. Knowing why someone uses is often the first step toward helping them.

What are the main reasons people use drugs?

NIDA groups the reasons people start into four categories. Each one points to a different kind of help.

To feel good. Drugs can produce intense feelings of pleasure.
To feel better. NIDA notes that some people with social anxiety, stress, or depression start using drugs to feel less anxious. Physical pain belongs here too. This is what people mean by "self-medicating."
To do better. Some people feel pressure to sharpen their focus at school or work, or to perform better in sports.
Curiosity and social pressure. Wanting to fit in, or simply wondering what a drug feels like. NIDA says teens are especially at risk because peer pressure can be very strong.

Source: NIDA, Drug misuse and addiction.

People with anxiety, depression, stress, or pain may turn to drugs especially when they can't get mental health care. Source: NIDA, Co-occurring disorders and health conditions. In 2025, 6.9 million people misused prescription opioids. Source: SAMHSA, 2025 NSDUH.

The reason can also change over time. Someone who started using to have fun may keep using to get through withdrawal or to feel normal. The next sections explain why.

Why do some people get addicted and others don't?

No single factor decides it. NIDA says the more risk factors a person has, the greater the chance that drug use will lead to addiction, and protective factors lower that risk. Even with several risk factors, addiction is not inevitable. Source: NIDA, Drug misuse and addiction; Source: NIDA, Prevention.

NIDA pairs common risk factors with the protective factors that offset them:

Aggressive behavior in childhood, offset by self-efficacy (confidence in your ability to cope)
Little parental supervision, offset by parental monitoring and support
Trouble saying no to peers, offset by positive relationships
Early drug experimentation, offset by good grades
Drugs easy to get at school, offset by school anti-drug policies
Community poverty, offset by neighborhood resources

Source: NIDA, Drug misuse and addiction.

SAMHSA's 2024 review of childhood risk factors adds family conflict, abuse or neglect, a family history of substance use, a parent's depression, and stressful life events such as the death of a parent. Source: SAMHSA, Risk and protective factors for substance use that present in childhood. On the protective side, NIDA points to traits like optimism, healthy family and peer relationships, and financial stability. Source: NIDA, Prevention.

Is addiction genetic?

Partly. NIDA estimates that genes, including the ways a person's environment changes how genes work (epigenetics), account for 40 to 60 percent of a person's risk of addiction. Source: NIDA, Drug misuse and addiction.

NIDA's source for that figure is a 2009 review by researchers at the National Institute on Alcohol Abuse and Alcoholism. It drew on family, adoption, and twin studies. In large surveys of adult twins, the estimated genetic share ranged from about 39 percent for hallucinogens to 72 percent for cocaine, and addiction did not follow a simple single-gene pattern of inheritance. Source: Clinical Pharmacology and Therapeutics, Genes and addictions, 2009.

Heritability is a population estimate. It does not mean someone with a family history has a 40 to 60 percent chance of addiction. It means family history is a real risk worth knowing about, not a fate. Learn more in our article Is addiction genetic?

Does starting young raise the risk?

Yes. NIDA says the earlier people begin using drugs, the more likely they are to develop serious problems, and early use is a strong sign of trouble ahead. The prefrontal cortex, which handles decision-making and emotional control, is still developing in the teen years, and drugs introduced then may change the brain in lasting ways. Source: NIDA, Drug misuse and addiction. That is why most prevention programs focus on delaying first use. Source: NIDA, Prevention.

How do childhood trauma and ACEs affect drug use?

Adverse childhood experiences (ACEs) are potentially traumatic events before age 18, such as abuse, neglect, or violence, or living with a parent who has a substance use problem. The CDC notes that ACEs can be prevented. Source: CDC, About adverse childhood experiences.

ACEs are common. In CDC survey data from 2011 to 2020, 63.9 percent of U.S. adults reported at least one ACE, and 17.3 percent reported four or more. Source: MMWR, Prevalence of ACEs among U.S. adults, 2023. In the original CDC-Kaiser ACE Study (2003), each ACE raised the odds of starting drug use early by 2 to 4 times. Adults with five or more ACEs were 7 to 10 times more likely to report addiction to illicit drugs than adults with none. Source: Pediatrics, ACEs and illicit drug use, 2003.

Long-lasting stress in childhood can affect brain development and the body's stress-response system. Source: CDC, About adverse childhood experiences.

How are mental health and drug use connected?

The connection runs both ways. NIDA describes three links: mental health conditions and substance use disorders share risk factors such as genes, trauma, and stress; mental health symptoms can lead people to use drugs; and drug use can trigger or worsen mental health conditions. Source: NIDA, Co-occurring disorders and health conditions.

It is common. In 2025, about two in five U.S. adults with a substance use disorder, 18.5 million people, also had a mental illness. Source: SAMHSA, 2025 NSDUH. NIDA says it is usually better to treat both at the same time. This is called dual diagnosis treatment.

How does drug use change the brain?

Drugs flood the brain's reward circuit with dopamine, which produces the high and "teaches" the brain to chase the drug over healthier rewards. With repeated use, the brain adapts:

Tolerance. The person needs more of the drug for the same effect. Eventually they may need it just to feel a normal level of reward.
Withdrawal. When the drug wears off, anxiety, irritability, and unease set in. Many people keep using for relief rather than to get high.
Less self-control. The prefrontal cortex, which handles planning and impulse control, works less well, so drug seeking becomes compulsive.

Source: NIDA, Drugs and the brain.

This is why NIDA calls addiction a brain disorder. The first decision to use is typically voluntary. Continued use, though, can seriously weaken a person's ability to stop, even when they want to. Source: NIDA, Drug misuse and addiction. The brain can recover, at least in part, after a long period without drugs. Source: NIDA, Treatment and recovery. For a closer look at specific drug classes, see how drugs affect the brain.

What are the signs that drug use has become a problem?

The clearest sign is continuing to use even though it is causing harm. MedlinePlus lists these warning signs:

Being unable to cut back or stop
Needing to use daily or regularly just to function
Continuing even when health, work, or family are being harmed
Missing work or school, or slipping performance
Dropping activities they used to enjoy
Making excuses to use, or using alone
Hiding use or being secretive
Neglecting meals or appearance
Getting hostile when someone raises the subject
Withdrawal symptoms when not using

Source: MedlinePlus, Substance use disorder.

For yourself, a useful test is this: is the reason you started still the reason you use? If you now use to avoid feeling sick, to get through the day, or because you can't stop, it may have become a substance use disorder. Our self-assessment guide, "Am I an addict?" walks through the questions clinicians ask.

How do you talk to someone about drug use without shaming them?

Lead with concern, not blame. MedlinePlus notes that denial is common, but people show far less of it when they are treated with empathy and respect rather than confronted or told what to do. Source: MedlinePlus, Substance use disorder. Stigma is one of the reasons people who need help don't seek it. Source: NIDA, Stigma and discrimination.

Words matter. NIDA recommends person-first language and letting people choose how they are described. Source: NIDA, Words matter.

Instead of "addict," say "person with a substance use disorder."
Instead of "drug abuse," say "drug use," or "misuse" for prescription medicines.
Instead of "clean" or "dirty," say "not using" or "abstinent," and "tested negative" or "tested positive."
Instead of "a bad habit," say "a substance use disorder."

Some practical ways to start:

Pick a calm, private moment when the person is sober and neither of you is rushed.
Describe what you've seen, specifically. "You missed work twice this week" lands better than "You're always high."
Ask what the drug does for them. Is it easing anxiety, pain, or sleeplessness? The reason points to what treatment needs to address.
Listen more than you talk. You don't need to win the conversation. The goal is to keep the door open.
Offer one concrete next step, such as a doctor's visit, an assessment, or a call to a helpline, and offer to go with them.
Look after yourself, too. Living with a loved one's drug use is stressful. When they do start treatment, family therapy helps the whole family learn healthier ways to communicate.

When should you seek help?

Reach out as soon as you or a loved one wants to cut back or stop, or when use keeps causing harm. Don't wait for things to get worse. MedlinePlus advises seeing a provider if someone using a substance wants to stop, or if they've been cut off from their supply and are at risk of withdrawal. Source: MedlinePlus, Substance use disorder.

Most people who need care don't get it. In 2025, only about 1 in 6 people who needed substance use treatment received it. Source: SAMHSA, 2025 NSDUH. Addiction is treatable. NIDA calls it a treatable disorder, with relapse rates similar to those of other chronic illnesses such as asthma and high blood pressure, and says a relapse does not mean treatment has failed. Source: NIDA, Treatment and recovery.

Overdose or medical emergency: call 911.
Suicidal thoughts or a mental health crisis: call or text 988, the Suicide and Crisis Lifeline.
Confidential treatment referrals: call SAMHSA's National Helpline at 1-800-662-4357. It is free, available 24/7, and offered in English and Spanish. Source: SAMHSA, National Helpline.

At Ambrosia, addiction treatment can begin with detox and continue through inpatient and outpatient programs. When anxiety, depression, trauma, or another mental health condition is part of the picture, our dual diagnosis program treats both together. You don't need to know which came first before you call.

Frequently asked questions

Why do teens use drugs?

Mostly for the same reasons adults do, but curiosity and peer pressure weigh more heavily, and the teen brain is still developing. NIDA says teens are especially at risk, and the earlier use starts, the higher the chance of serious problems later. Source: NIDA, Drug misuse and addiction.

Is addiction a choice?

The first use usually is, but addiction is not. NIDA describes addiction as a brain disorder in which repeated use weakens self-control and drives compulsive use despite harm. Source: NIDA, Drug misuse and addiction.

Do people use drugs to self-medicate?

Often, yes. People with anxiety, depression, stress, or pain may use drugs to feel better, especially when they lack mental health care. Drug use can also make those conditions worse. Source: NIDA, Co-occurring disorders and health conditions.

Does everyone who uses drugs become addicted?

No. NIDA says no single factor determines whether a person becomes addicted. Risk rises with each added risk factor, such as family history, early use, trauma, or a mental health condition, and protective factors lower it. Source: NIDA, Drug misuse and addiction.