Substance Use Disorders: Defining Terms and Getting Treatment

Medically Reviewed By Alyssa Peckham, PharmD, BCPP
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Substance use disorders are conditions in which changes in brain chemistry cause people to misuse drugs or alcohol. Someone with a substance use disorder finds it difficult to stop using substances, even when they cause harm. Healthcare professionals classify substance use disorders as mental health conditions, and effective treatment options are available. Other terms related to this condition include drug addiction and substance misuse. However, these terms are not synonymous.

The Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) classifies the condition as a substance use disorder, with varying levels of severity under that term.

This article provides an overview of substance use disorders. It includes treatment options, tips on how to get help, and information on how doctors define different stages of substance use.

What are substance use disorders?

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The DSM-5 defines substance use disorders within a class of conditions “related to the taking of a drug of abuse (including alcohol).” It also lists classes of substances that fall under this category, including:

  • alcohol
  • stimulants, such as cocaine or amphetamines
  • cannabis
  • inhalants
  • opioids, including heroin and some types of prescription pain medication
  • sedatives, tranquilizers, and depressants, including benzodiazepines and barbiturates
  • caffeine
  • tobacco

The Surgeon General’s Report on Alcohol, Drugs, and Health notes that a substance use disorder is a clinical condition and not a flaw in a person’s character or morality. The symptoms of substance use disorders result from chemical changes in the brain that affect someone’s ability to manage their substance use.

Substance use, misuse, and addiction

Substance use disorders can range from mild to severe, and different terms describe different levels of use.

Research that appears in Transactions of the American Clinical and Climatological Association distinguishes the levels of substance use as follows:

  • Substance use: This is a term that describes the use of any type of substance that alters mood.
  • Substance misuse: This is a term for when the use of a substance causes the person harm or puts others at risk, such as binge drinking or driving when drunk.
  • Addiction: This is a term for a chronic or severe substance use disorder in which the person can no longer manage their substance use.

Addiction means that your body has become dependent on a substance to the point where not having it can put your body in a state of physical withdrawal. This is in addition to experiencing cravings that drive continued use despite harmful outcomes.


Experts estimate that about 40.3 million people aged 12 years and older in the United States have a substance use disorder. The National Institute on Drug Abuse (NIDA) notes that the COVID-19 pandemic may result in this number becoming even higher.

If you or someone you know is experiencing substance misuse or addiction, take action. Early intervention is the most effective way to treat substance use disorders and slow the progression of symptoms.

Learn about the differences between addiction and physical dependence here.

Treatments and how to get help

Researchers define a severe substance use disorder as a chronic condition that does not have a cure. However, someone with a substance use disorder can manage their symptoms with effective treatment.

Treatment for substance use disorders can vary depending on the type of disorder you have, your medical history, and your personal needs.

NIDA notes that about half of people with a substance use disorder also have at least one other mental health condition, such as anxiety, depression, attention deficit hyperactivity disorder (ADHD), or bipolar disorder. NIDA goes on to explain that in these cases, treatment focuses on addressing both conditions together.

Screening and early intervention

The Surgeon General’s Report on Alcohol, Drugs, and Health recommends early intervention for symptoms of substance misuse or a mild substance use disorder. Such symptoms may include episodes of binge drinking or drinking alcohol while pregnant.

Because early intervention improves treatment outcomes, the U.S. Preventive Services Task Force recommends routine screening of everyone over the age of 12 years for symptoms of substance misuse and substance use disorders. They suggest that these screenings take place during primary care visits.

Depending on the severity, treatment for a substance use disorder may occur on an inpatient or outpatient basis at a hospital or a specialty treatment facility. In cases of mild or moderate substance use disorders, your primary care physician may be able to provide treatment. Telehealth treatment is another option, particularly for people who are concerned about COVID-19.

In any setting, treatment for substance misuse and substance use disorders typically focuses on medication with or without behavioral therapy.

Medications to treat substance use disorder 

Several medications have Food and Drug Administration (FDA) approval to treat alcohol and opioid use disorders. These medications include:

Medications for opioid use disorderMedications for alcohol use disorder
Methadone: This is a synthetic opioid that helps reduce cravings, block the effects of other opioids, and manage withdrawal symptoms. People often use this medication long term from specialty clinics.Disulfiram: This is a medication for alcohol use disorder. It does not treat the root cause of the illness or reduce cravings. Instead, it creates illness by producing unpleasant symptoms if a person drinks alcohol.
Buprenorphine: This is a partial opioid agonist that helps reduce cravings, block the effects of other opioids, and manage withdrawal symptoms. People often use this medication long term from primary care and specialty clinics.Acamprosate: This is a medication that reduces cravings for alcohol among people who are in recovery from alcohol use disorder.
Naltrexone: This is an opioid antagonist that helps reduce cravings from opioids and block the effects of other opioids. People often use this medication long term as a once-monthly injection for both opioid and alcohol use disorders.Naltrexone: This is an opioid antagonist that helps reduce cravings from alcohol. People often use this medication long term as a once-monthly injection or pill for alcohol use disorder.

Naloxone for opioid overdose

Naloxone is an FDA-approved opioid receptor antagonist that works as an emergency treatment for opioid overdose. The drug binds to opioid receptors and rapidly reverses the toxic effects of opioids.

Naloxone is available as an injection or a nasal spray. In states that have enacted naloxone access laws, deaths from opioid overdose have decreased by 14%.

If you or a family member uses opioids, talk with a doctor about having access to naloxone, which can provide life saving treatment for someone at risk of opioid overdose.

Behavioral therapies for substance use disorder

The National Institute of Mental Health lists the following behavioral therapy options:

  • Cognitive behavioral therapy: This is a type of talk therapy that helps you learn to reframe irrational thoughts and change your behaviors.
  • Dialectical behavioral therapy: This is a type of therapy that teaches you skills to control your emotions and behaviors while being aware of your emotional state.
  • Community-based treatment: This includes assertive community treatment, which makes use of community outreach, and therapeutic communities therapy, which involves long-term residential treatment.
  • Contingency management: This is a process that offers rewards for achieving substance use goals.
  • Family therapy: This includes both the person with a substance use disorder and their family to address concerns and plan recovery strategies together.
  • Recovery support: This includes follow-up visits with therapists and other support systems to ensure continued success after treatment.

Only about 1 in 10 people with a substance use disorder receive treatment. This can be due to social stigma and shame around substance misuse and addiction. Factors also include a lack of available programs, a lack of money or insurance to pay for them, or a lack of awareness about treatment options. Many people also wait until a major crisis, such as a legal offense or overdose, to seek help.

How to get help

If you are seeking help for yourself or a loved one, you have several resources available to you. For example:

What causes substance use disorder?

Researchers have studied brain images from people who have a severe substance use disorder, or addiction. These images show physical changes over time to the areas of the brain related to behavior control, decision making, memory, learning, and judgment.

The Surgeon General’s Report on Alcohol, Drugs, and Health explains that certain substances trigger surges of dopamine, which is a neurotransmitter associated with processing rewards and controlling how we receive rewards.

The Report goes on to say that the repeated use of certain substances makes this area of the brain less sensitive to dopamine. As a result, a person needs to use more of the substance to create the same feeling of euphoria, or “high,” from the substance.

Eventually, when a person is not using the substance, they experience emotional or physical distress, which is a state called withdrawal. During this period, a person may be compelled to use drugs or alcohol to relieve these negative feelings.

Risk factors

Brain development is not complete until about 21–23 years of age in females and 23–25 years of age in males. One of the last regions to mature is the prefrontal cortex, which is responsible for being able to delay rewards and to reason. Someone who starts using substances while their brain is still developing, such as during their teenage years, is at much higher risk of affecting those critical circuits and developing a substance use disorder. 

Research cited by the Surgeon General shows that nearly 70% of those who try illegal drugs before the age of 13 years develop a substance use disorder in the next 7 or so years. This is in comparison with 27% of people who develop a substance use disorder after first trying an illegal substance when they are age 17 years or older.

NIDA lists these additional risk factors for developing a substance use disorder:

  • genetic factors, which researchers estimate to account for about 40–60% of a person’s risk of developing a substance use disorder
  • a lack of parental supervision or stability at home
  • exposure to sexual or physical abuse
  • a family history of substance use or mental health conditions
  • aggressive childhood behavior
  • living in an area of poverty
  • the availability of drugs in school
  • peer groups who use drugs or alcohol
  • social isolation
  • current mental health condition(s)

NIDA also notes that the method that someone uses to take a drug can affect its potential to become addictive. For example, smoking or injecting a substance produces a more rapid, powerful high, which increases the risk of developing a substance use disorder.

Protective factors

There are also some positive influences that can help prevent someone from developing a substance use disorder.

NIDA outlines these protective factors that reduce someone’s risk:

  • self-efficacy, or a person’s belief that they have self-control
  • parents or caregivers who are present and who offer nurturing support
  • positive social relationships
  • good academic performance
  • anti-drug policies and messaging at school
  • a thriving community with available resources

What substances do people misuse?

The Drug Enforcement Administration provides detailed information about substances that people misuse, which are known as “drugs of abuse.”

Some of these drugs include:

  • alcohol
  • cannabis
  • hallucinogens, such as PCP and LSD
  • inhalants, such as paint thinners and glue
  • opioid pain relievers, including heroin and prescription pain relievers, such as fentanyl (an illegal form of which is implicated in the majority of opioid overdose deaths), codeine, and oxycodone (OxyContin)
  • sedatives, tranquilizers, and other anxiety medications
  • cocaine, methamphetamine, and other stimulants
  • tobacco

Symptoms of substance use disorder

The American Psychiatric Association (APA) revised their classification of substance use disorder in 2013 as part of their most recent update to the DSM-5

The new APA guidelines include 11 symptoms of substance use disorder. These are:

  • using substances in larger amounts or for longer than intended
  • wanting to cut down or stop using the substance but not being able to
  • spending a lot of time to get or use a substance or to recover from use
  • craving or having a strong urge to use the substance
  • not being able to manage other commitments due to substance use
  • continuing to use a substance, even when it causes issues in relationships
  • giving up important activities in order to use a substance
  • continuing to use a substance, even when it puts you in danger
  • continuing to use a substance, even when it may worsen physical or psychological problems
  • developing an increasing tolerance, or needing to use larger amounts to get the same effect
  • experiencing withdrawal symptoms if you try to stop using the substance

Doctors make a diagnosis based on an assessment of the number of symptoms a person experiences from this list:

Number of symptomsDiagnosis
fewer than 2no substance use disorder
2–3a mild substance use disorder
4–5a moderate substance use disorder
6 or morea severe substance use disorder, or addiction

Symptoms of opioid overdose

The Centers for Disease Control and Prevention (CDC) reports that opioids were a factor in more than 70% of all overdose deaths in 2019. However, treatment for opioid overdose is possible with quick action.

The CDC lists some symptoms of opioid overdose. Seek emergency care (call 911) right away for any of the following symptoms:

  • breathing that is very slow and shallow
  • choking or making gurgling sounds
  • falling asleep or becoming unconscious
  • going limp
  • having skin that is pale, blue or discolored, or cold
  • having small, constricted pupils that resemble pinpoints

The CDC outlines the following steps to take if you suspect or know of opioid overdose:

  • Call 911.
  • If naloxone is available, administer it. Naloxone can rapidly reverse the effects of opioids and is available as an injection or a nasal spray.
  • Place the person on their side to prevent choking.
  • Stay with the person until help arrives.

Complications of substance use disorder

Having a substance use disorder can double the risk of developing many chronic and serious conditions, including: 

NIDA explains that substance misuse can cause a person to engage in dangerous or risky behaviors, which, in turn, can increase the risk of conditions or harmful events such as:


Substance use disorders are conditions in which chemical changes in the brain cause a person to use alcohol or drugs despite them producing harmful effects.

Symptoms of substance use disorders can range from mild to severe. When they are severe, doctors may refer to the condition as addiction. At this stage, a person is unable to manage their use of drugs or alcohol.

Several risk factors can make a person more likely to develop a substance use disorder, including starting to use drugs or alcohol at a younger age, having a family history of substance use, experiencing social isolation, experiencing community poverty, and having exposure to physical or sexual abuse.

Doctors diagnose substance use disorders based on the quantity and severity of symptoms. Treatment is effective and may include medication with or without behavioral therapy.

If you suspect that you or someone you care about may be misusing substances or could be developing a substance use disorder, help is available. You can contact your primary care professional or the federal government’s 24/7 substance use helpline at 800-662-HELP (4357).

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Medical Reviewer: Alyssa Peckham, PharmD, BCPP
Last Review Date: 2022 Jan 28
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