An Overview of Substance Use

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Substance abuse can simply be defined as a pattern of harmful use of any substance for mood-altering purposes. "Substances" can include alcohol and other drugs (illegal or not) as well as some substances that are not drugs at all.

"Abuse" can result because you are using a substance in a way that is not intended or recommended, or because you are using more than prescribed. To be clear, someone can use substances and not be addicted or even have a substance use disorder, as defined in the "Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition" (DSM-5).

This article discusses what constitutes harmful substance use, illegal substance use, and prescription drug misuse. It also covers some of the substances that are more frequently abused as well as the risks of substance misuse.

What Is Harmful Use?

Health officials consider substance use as crossing the line into substance abuse if that repeated use causes significant impairment, such as:

  • Disabilities
  • Failure to meet responsibilities
  • Health issues
  • Impaired control
  • Risky use
  • Social issues

In other words, if you drink enough to get frequent hangovers; use enough drugs that you miss work or school; smoke enough marijuana that you have lost friends; or often drink or use more than you intended to use, your substance use is probably at the abuse level.

However, the broad range of substance abuse in today's society is not that simple.

Illegal Drug Use

Generally, when most people talk about substance abuse, they are referring to the use of illegal drugs. Drugs of abuse do more than alter your mood. They can cloud your judgment, distort your perceptions, and alter your reaction times, all of which can put you in danger of accident and injury.

These drugs got to be illegal in the first place because they are potentially addictive or can cause severe negative health effects. Some believe the use of illegal substances is considered dangerous and, therefore, abusive.

In the United States, the most commonly abused illegal drugs, in order, are:


Substance abuse usually refers to the use of illegal drugs such as cocaine, heroin, and methamphetamine. These substance are illegal because of their high risk for abuse and dangerous side effects.

Recreational Drug Use

Some people argue that casual, recreational use of some drugs is not harmful and is merely use, not abuse. The most vocal of the proponents of recreational drug use are those who smoke marijuana. They argue that marijuana is not addictive and has many beneficial qualities, unlike the "harder" drugs.

But recent research has shown that even marijuana may have more harmful physical, mental, and psychomotor effects than first believed. Each year, new scientific studies find more ways that long-term marijuana use is harmful to your health.

In addition, the National Institute on Drug Abuse (NIDA) reports that people who use marijuana can become psychologically dependent, and therefore addicted. NIDA estimates that 9% of people who use marijuana will become dependent, and the percentage rises to 17% for those who began using the drug in their teens.

Prescription Substance Misuse

Prescription substance misuse has risen substantially over the last few decades. The National Institute on Drug Abuse estimates that between 8% to 12% of U.S. patients who are prescribed opioid pain relievers develop a substance use disorder.

According to the CDC, the number of opioid-related deaths increased by 5% between 2018 and 2019, with an average of 38 people dying each day from prescription opioid overdoses in 2019.

In the U.S., there are three main classes of prescription drugs commonly misused: Opioids, central nervous system depressants, and stimulants. According to NIDA, these include:


Substance abuse can also involve misusing prescription medications that have the potential for dependence.

Other Commonly Abused Substances

Alcohol, prescription, and over-the-counter medications, inhalants and solvents, and even coffee and cigarettes can all be used to harmful excess. In fact, many children have their first encounter with substance abuse by using inhalants, simply because they are found in many common household products and, therefore, readily available.


Alcohol is, of course, legal for adults over the age of 21 in the United States, and there is nothing "wrong" with having a couple of drinks with friends or to unwind on occasion. But, it doesn't take much alcohol to reach a harmful level of drinking, and that is when alcohol use can turn into alcohol abuse.

Drinking five or more drinks for men (four for women) in any one sitting is considered binge drinking, which can be harmful to your physical and mental health in many different ways.


Nicotine is the single most abused substance in the world. Although smoking has declined in recent years, it is estimated that 40 million Americans are still addicted to nicotine in spite of its well-publicized harmful effects.

Again, just because it is legal, doesn't mean it can't be abused. The fact that the negative health effects of nicotine take a long time to manifest probably plays a role in the widespread abuse of tobacco.


Whereas nicotine is the most abused drug, caffeine is the most commonly used mood-altering drug in the world. And yes, too much caffeine can be harmful to your health.

Studies have also found a link between caffeine use and several psychiatric syndromes, including caffeine-induced sleep disorder and caffeine-induced anxiety disorder. People diagnosed with generalized anxiety disorder, panic disorder, primary insomnia, and gastroesophageal reflux are usually advised to reduce or eliminate regular caffeine use.


In today's culture, we now have "designer drugs" and synthetic drugs, such as bath salts and synthetic marijuana, which may not yet be illegal, but can certainly be abused and can possibly be more dangerous.

Other designer drugs commonly misused include:

  • Amphetamines
  • Ecstasy
  • LSD
  • GHB
  • Ketamine
  • Rohypnol (date rape drugs)
  • PCP

Anabolic Steroids

There are also substances that can be abused that have no mood-altering or intoxication properties, such as anabolic steroids. The use of anabolic steroids to enhance performance or develop muscles and strength is abusive because of the negative side effects of their use, which can range from merely annoying to life-threatening in some cases. If it can cause you harm, even in the long term, it is substance abuse. Theoretically, almost any substance can be abused.


Substance abuse often involves substances including alcohol, nicotine, caffeine, synthetic drugs, and anabolic steroids. 

Risks of Substance Misuse

When it comes to illegal substances, society has determined that their use is harmful and has placed legal prohibitions on their use. This is to both protect individuals' wellbeing and shield society from the costs involved with related healthcare resources, lost productivity, the spread of diseases, crime, and an increased risk of homelessness (although the impact of criminalizing this use has been open to considerable controversy).

For many legal substances, the line between use and abuse is not clear. Is having a couple of drinks every day after work to unwind use or abuse? Is drinking two pots of coffee in the morning, to get your day started, use or abuse? Is smoking a pack of cigarettes a day substance abuse?

Generally, in these situations, only the individual himself can determine where use ends and abuse begins. The question to ask yourself is, "Is this causing me harm?" or resulting in any of the following:

  • Physical health problems: Substance abuse can increase the risk of physical health issues including heart disease, stroke, and cancer.
  • Mental health problems: Substance use often co-occurs with mental health problems, but it can also worsen or contribute to the onset of some conditions as well.  
  • Risky or dangerous behavior: Substance can also increase the risk of risky behaviors such as driving while intoxicated and engaging in unprotected sex.
  • Legal risks: When using illicit substances, people face an increased risk of legal consequences which can include arrest and incarceration.


Substance abuse poses both individual and societal risks. For individuals, it can lead to health problems, mental health issues, risky behavior, and legal problems. For societies, substance abuse can increase the costs associated with health problems and lost productivity. It can also contribute to social problems such as crime.

A Word From Verywell

Has your substance use become harmful? If you think this may be true for you, you are certainly not alone. According to the latest estimates, about 27.1 million Americans—approximately one in every 10 people—misuse substances.

Are you hesitant to seek help for your substance use? Again, you are not alone. In 2015, an estimated 21.7 million people needed substance use treatment, but only three million actually received any treatment. If you have tried to quit or cut back on your own and found you were not able to do so, you may want to try other options and learn more about treatment for substance abuse.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

For more mental health resources, see our National Helpline Database.

Frequently Asked Questions

  • What is substance abuse?

    The most common definition is a pattern of harmful use of any substance for mood-altering purposes. In this case, substance can include alcohol, prescription and over-the-counter drugs, illegal drugs, inhalants and solvents, and even coffee and cigarettes.

  • What is a substance use disorder?

    The DSM 5 recognizes substance-related disorders resulting from the use of 10 separate classes of drugs: alcohol; caffeine; cannabis; hallucinogens (phencyclidine or similarly acting arylcyclohexylamines, and other hallucinogens, such as LSD); inhalants; opioids; sedatives, hypnotics, or anxiolytics; stimulants (including amphetamine-type substances, cocaine, and other stimulants); tobacco; and other or unknown substances.

    Substance use disorders span a wide variety of problems arising from substance use and cover 11 different criteria, according to the DSM 5.

  • What causes substance abuse?

    Substance abuse is a complex problem that is influenced by a number of factors. There is no way to predict who will become addicted to drugs, but a combination of influences can increase a person's risk of developing an addiction. Genes, the presence of other mental health conditions, developmental factors, and environmental influences all play a role. 

  • How can people prevent substance abuse?

    Family history, peer pressure, and recreational drug use are all risk factors for substance abuse. Being aware of these risks can help you take steps to avoid using substances in the first place. Seeking treatment for mental health conditions can also play a role in prevention. If you use substances for recreational purposes, misuse prescription medications, or take substances for the purposes of becoming intoxicated, you should talk to your doctor about your treatment options.

  • How is substance use treated?

    Treatment for substance abuse may involve behavioral therapies, medications, or a combination of different approaches. Cognitive behavioral therapy (CBT), contingency management, and motivational enhancement therapy are a few types of therapy that may be used. Medications are also available that can help people with opioid, nicotine, or alcohol addiction.

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14 Sources
Verywell Mind 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. McLellan AT. Substance Misuse and Substance use Disorders: Why do they Matter in Healthcare?Trans Am Clin Climatol Assoc. 2017;128:112–130.

  2. Csete J, Kamarulzaman A, Kazatchkine M, et al. Public health and international drug policyLancet. 2016;387(10026):1427–1480. doi:10.1016/S0140-6736(16)00619-X

  3. National Institute on Drug Abuse. Marijuana research report: Is marijuana addictive?

  4. Vowles KE, McEntee ML, Julnes PS, Frohe T, Ney JP, van der Goes DN. Rates of opioid misuse, abuse, and addiction in chronic pain: a systematic review and data synthesisPain. 2015;156(4):569-576. doi: 10.1097/01.j.pain.0000460357.01998.f1. PMID: 25785523

  5. CDC. Prescription opioid overdose death maps.

  6. National Institute on Drug Abuse. Misuse of Prescription Drugs Research Report: Overview.

  7. Conn RB. Inhalant use disorders. In: Avery JD, Hankins D, eds. Addiction Medicine. Vol 2. Springer International Publishing; 2022:57-65. doi:10.1007/978-3-030-86430-9_6

  8. Lachenmeier DW, Rehm J. Comparative risk assessment of alcohol, tobacco, cannabis and other illicit drugs using the margin of exposure approachSci Rep. 2015;5:8126. doi:10.1038/srep08126

  9. Bergin JE, Kendler KS. Common psychiatric disorders and caffeine use, tolerance, and withdrawal: an examination of shared genetic and environmental effectsTwin Res Hum Genet. 2012;15(4):473–482. doi:10.1017/thg.2012.25

  10. National Institute on Drug Abuse. What are anabolic steroids? Anabolic Steroids DrugFacts.

  11. Lipari, R. N., Park-Lee, E., and Van Horn, S. America’s need for and receipt of substance use treatment in 2015. The CBHSQ Report: September 29, 2016. Center for Behavioral Health Statistics and Quality, Substance Abuse and Mental Health Services Administration, Rockville, MD.

  12. John Hopkins Medicine. Substance abuse / chemical dependency.

  13. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 5th ed. Washington, DC.

  14. National Institute on Drug Abuse. Understanding drug use an addiction. DrugFacts.

Additional Reading
  • John Hopkins Medicine Behavioral Pharmacology Research Unit. "Caffeine Dependence." Fact Sheet 2016
  • Substance Abuse and Mental Health Services Administration. "Substance Use Disorders." Mental and Substance Use Disorders October 2015
  • World Health Organization. "Substance abuse." Health Topics 2016