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The Facts About Substance Use and Addiction

Find out how substance use and addiction affect your sexual health.

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Misusing substances can negatively impact every part of your life, from your mental and physical health to your sexual health and personal relationships; or even your ability to carry out daily responsibilities at work, school and home.

It’s estimated about 50 percent of Americans, ages 12 and older, have used illicit drugs at least once and that the number of overdose deaths in the U.S. since 2000 is approaching 1 million. The government’s 2023 budget supports spending $42.5 billion for National Drug Control Program agencies to implement drug control policies.

What is drug addiction?

Drug addiction, known as substance use disorder, is a disease that impacts an individual's brain and behavior.

People with substance use disorder are unable to control their use of one or more drugs, including both legal and illegal drugs. Some commonly abused substances include alcohol, nicotine, marijuana, prescription drugs and other illicit street drugs.

When a person has a drug addiction, they often continue to use a drug despite knowing the harm that they're bringing on themselves.

Facts and stats

Unfortunately, drug addiction is not an uncommon problem in the United States. In fact, the Substance Abuse and Mental Health Services Administration's (SAMHSA) most recent survey on drug use and health indicated 46.3 million people aged 12 or older met the official criteria for having a substance use disorder in 2021, or about 16.5 percent of the population.

Of the people with a substance use disorder who were surveyed, 29.5 million individuals suffered from an alcohol use disorder, while 24 million had some sort of drug use disorder.

It's important to note that while all individuals suffering from drug addiction abuse substances, some people may have a substance use problem without reaching the point of addiction. Some examples include occasional binge drinking and experimenting with using prescription pills to get high, plus the use of "party drugs" or using any substance in a way that was not originally intended to be used.

SAMHSA's survey found that 61.2 million people used illicit drugs in 2021, while 9.2 million reported misusing opioids at some point in 2021, too.

A history of substance use

Substance use has existed for as long as humans have been around. However, in recent years, there have been multiple drug epidemics with far-reaching consequences that continue to be felt today.

Some notable examples include the crack epidemic of the 1980s and 1990s, which disproportionately affected lower-class, urban, Black neighborhoods. And then came the opioid crisis, which has impacted nearly every racial and socioeconomic demographic group in the U.S.

Though the use of opium can be traced as far back as 8,000 years ago, it was in 2017 when the U.S. Department of Health and Human Services declared the modern opioid epidemic—which began in the 2000s and 2010s—as a public health emergency, one that is still ongoing.

Overdose deaths involving opioids rose from 21,089 in 2010 to 47,600 in 2017. There was a significant increase in 2020 to 68,630. A year later that number had climbed to 80,411.

What substances are associated with substance use disorder?

There are several drugs associated with substance use disorder—many of which are perfectly legal. For example, alcohol and nicotine are often abused and can be easily purchased by adults who are of legal age.

Other drugs associated with substance use include illicit street drugs. Prescription drugs can be misused if they are taken in a way other than how they were originally prescribed or if taken by someone not prescribed the drug in the first place.

The National Institute on Drug Abuse reports that these are some of the most commonly abused substances:

  • Alcohol
  • Ayahuasca
  • Benzodiazepines are central nervous system depressants sometimes referred to as "benzos." Brand name products include Ativan, Valium and Xanax.
  • Cocaine
  • Hallucinogens
  • Heroin
  • Lysergic acid diethylamide, also known as LSD or acid.
  • Marijuana
  • MDMA (ecstasy)
  • Methamphetamine
  • Prescription opioids
  • Prescription stimulants, such as amphetamines, the most well-known being amphetamine sulfate (more commonly known on the street as speed).

Causes and risks

There is no single cause of substance use disorder. Medical experts believe a variety of factors contribute to the development of substance use disorders. These factors include genetic predisposition, environmental stressors, individual personality, social pressures and mental health problems.

Some risk factors for substance use disorder include:

  • A family history of addiction.
  • Being prescribed a highly addictive drug and using it legitimately, but still becoming addicted.
  • Being susceptible to peer pressure.
  • Certain mental health disorders such as depression, post-traumatic stress disorder and attention-deficit/hyperactivity disorder (ADHD).
  • Having an inadequate support system.
  • Using substances at a young age.

The warning signs of abusing prescription drugs

Abuse can occur when an individual takes a prescription drug in a way that was not intended by the medical professional who prescribed it. Often, this looks like taking higher doses of the drug than originally prescribed, taking the drug more frequently than prescribed or mixing the drug with other substances for a more powerful effect.

Here are some of the most common warning signs of prescription drug abuse:

  • Decreasing effectiveness, requiring more of the drug to feel its intended effect.
  • Growing dependence on a drug.
  • More frequent use of a drug than was originally prescribed.
  • Multiple failed attempts at cutting back on or quitting a drug.
  • Neglecting personal responsibilities at home, school or work to take a drug.
  • Performing out-of-character actions—such as stealing—to get a drug.
  • Spending more money than you can afford to keep a constant supply of a drug.
  • Withdrawal symptoms when you stop taking a drug.

How are genetics involved?

Research has found that having a family history of drug addiction, especially when it's a close relative, puts an individual at a significantly higher risk for developing substance use problems themselves.

Though research is still underway on this connection, medical experts believe that certain genetic traits may be responsible for slowing down or speeding up the progression of addiction once an individual has already begun taking a drug.

Of course, being at risk for addiction does not mean an individual will become addicted. Rather, they might be more vulnerable to the disease and may benefit from taking care to mitigate their risk.

Signs and symptoms

The signs and symptoms of substance use disorder can vary widely depending on the substance being abused. That being said, many common substances can cause similar symptoms when they are misused.

Here are some common signs and symptoms of drug abuse:

  • A sense of euphoria or feeling "high"
  • Anxiety or agitation
  • Confusion
  • Constipation
  • Diarrhea
  • Difficulty carrying out daily activities due to the use of the drug
  • Extreme mood changes
  • Growing dependence on a drug
  • Hallucinations
  • Irregular heartbeat
  • Nausea
  • Paranoia
  • Tremors
  • Trouble fulfilling work, school, social and other personal responsibilities due to the use of the drug
  • Violent behavior

When to call the doctor

If you experience any symptoms of substance use disorder or are concerned in any way about your substance use, contact your doctor right away. Effective treatment and support are available, and getting treatment as early as possible is essential to avoid potential complications of substance use disorder and drug addiction.

Diagnosis and testing

Substance use disorder can only be diagnosed following a thorough evaluation, which typically includes assessments carried out by medical professionals such as psychiatrists, psychologists, or licensed alcohol and drug counselors.

During the evaluation, blood, urine and other lab tests may be administered to determine an individual's level of drug use. If an individual meets the criteria for substance use disorder as outlined in the Diagnostic and Statistical Manual of Mental Health Disorders (DSM-5), then they will receive a formal diagnosis.

Treatments and therapies

Treatment for substance use disorder should vary based on an individual's unique needs, according to the National Institute on Drug Abuse. This means addiction problems should be viewed as one part of a larger picture, which may include many contributing or agitating factors such as mental health issues, family problems, lack of resources and more.

Substance use disorder is typically treated with one or more of the following methods:

  • Cognitive behavioral therapy (CBT)
  • Motivational enhancement therapy (MET)
  • Self-help groups
  • Twelve-step programs
  • Withdrawal therapy

Substance abuse prevention and aftercare

The only surefire way to prevent substance use disorder is to abstain from using substances.

However, if you do choose to use substances—or, for example, you require various prescribed substances for medical treatment—then there are things you can do to protect yourself.

First, be sure to use substances only as intended. You should educate yourself about substance use disorder and its harmful effects and consequences. Critically, you need to be able to recognize early warning signs of substance use disorder so you can reach out for help right away if you notice any of such symptoms.

For people recovering from substance use disorder, it's important to remember recovery never ends. It will require active and ongoing effort to remain in recovery.

Whether you are living with substance use disorder yourself, or you're coping with a loved one's substance use disorder, be sure to lean on your support system, use resources and make a plan for how you'll avoid falling into old habits.

Clinical trials and research on substance abuse

Clinical trials are an important tool used in medical research to further the understanding of diseases such as addiction and substance use disorders. 

If you're interested in participating in a clinical trial, explore this government database of privately and publicly funded active clinical trials. 

Before participating in a clinical trial, be sure to consult your doctor and loved ones, and move forward with your own best interest at heart.

Resources for patients and caregivers

Education is a great first step toward seeking help for substance use and addiction. There are many online resources available and here are five recommended websites to start your journey:


What is the difference between drug addiction and substance use?

Substance use occurs when a person uses illicit drugs or misuses medication. Drug addiction, on the other hand, is a serious disease that affects both the brain and the behavior of the person suffering from it. All people addicted to drugs abuse substances, but not all those who abuse substances become addicted.

What are the three types of addiction?

The various types of addiction disorders can fall under three umbrellas: substance addictions, behavioral addictions and impulse control disorders. Substance addictions may include alcoholism or opioid addiction, while behavioral addictions include disorders such as shopping or sex addictions. Lastly, impulse control disorders include conditions such as an addiction to gambling.

What is an example of abusing a substance?

Examples of substance use include taking party drugs such as MDMA (ecstasy), binge drinking during a night out or misusing prescription stimulants to stay up late to cram for an exam at college.