Substance use disorder (SUD) affects a person’s ability to control their use of alcohol or drugs. SUD can affect various areas of a person’s life, such as work, school, or family responsibilities. Treatment can include medication and psychotherapy.

The severity of SUD symptoms and their impact on a person’s life can vary. In some cases, SUD can become life threatening.

This article looks at what SUD involves and its symptoms and treatment options.

A person silhouetted by dots of light. People with substance use disorders (SUDs) may experience withdrawal symptoms if they stop taking a substance suddenly.Share on Pinterest
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SUD is a condition that involves a person’s misuse of substances, such as alcohol or drugs, even though the person may continue to experience unwanted harmful effects.

Continued use of the substance may affect a person’s behaviors, physical health, and ability to function in day-to-day life. Addiction is the most severe form of SUD.

Substances may be illegal or legal, such as prescription medication. In the United States, alcohol is the most commonly misused substance by people with SUD.

SUD is very common. In the United States, 1 in 7 people aged 12 years and older report having an SUD. The condition can affect any person regardless of age, race and ethnicity, income level, or gender.

Symptoms of SUD can vary based on the substance and person. They can include physical, emotional, and social aspects. The severity of symptoms may also differ.

Healthcare professionals diagnose SUDs using criteria from the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR).

A person must meet at least two of the DSM-5-TR criteria over a 12-month period. These criteria include:

  • Taking greater amounts: The person uses more of the substance than intended or for longer periods than planned.
  • Cravings: A person experiences a strong desire for the substance.
  • Trouble stopping: A person wants to stop taking the substance but has not been able to on multiple attempts.
  • Responsibilities: A person cannot fulfill their responsibilities due to the substance.
  • Takes up a significant amount of time: A person spends a great amount of time trying to obtain the substance or recovering from its effects.
  • Giving up hobbies: A person gives up activities or reduces them due to substance use.
  • Work or social effects: A person continues using the substance despite it impairing their work or social life.
  • High risk use: A person uses the substance in situations that may result in unintended harmful consequences, such as while driving or at work.
  • Physical and mental health effects: A person continues to use the substance despite harmful effects on their physical and mental health.
  • Tolerance: A person develops a tolerance to the substance and needs increasing amounts to feel the same effect.
  • Withdrawal symptoms: A person experiences withdrawal symptoms after stopping taking the substance.

The number of criteria a person meets determines the severity of the SUD.

It is not always easy to recognize the signs of drug use. Some people with SUD engage in secretive behavior to hide their drug use.

Signs may differ based on the substance. Below are some common signs of drug use for specific classifications of drugs.

However, it is important to note that not everyone who uses these substances may have an SUD.


Cannabis comes in different forms. In some U.S. states, cannabis is legal.

People can smoke cannabis, inhale vapors, or eat cannabis in edible form. Signs of cannabis use include:


Stimulants are drugs that increase the activity of the central nervous system. Stimulants include both legal and illegal substances.

Legal prescription stimulants include:

Illegal stimulants include methamphetamine and cocaine.

Signs of stimulant use can include:

  • dilated pupils
  • talkativeness
  • increased energy
  • hypersensitivity to sound, sight, and touch
  • weight loss
  • dry mouth
  • irritability


Hallucinogenics, or psychedelics, are a group of drugs that alter someone’s perception of their thoughts and feelings as well as what’s around them.

Examples of hallucinogens include:

Signs of hallucinogenic use can include:

MDMA (ecstasy)

MDMA acts as a hallucinogenic and as a stimulant. Ecstasy is a common name for MDMA. The drug distorts perception and time.

Common signs of MDMA use can include:


Opioids include a class of drugs that reduce pain and relax the body. Opioids include both legal and illegal substances. Examples of opioids include:

Signs of opioid use can include:


Inhalants include volatile substances that produce chemicals, which a person can inhale to produce mind-alerting effects. Inhalants may be aerosols, gases, or nitrates.

Examples of inhalants include:

Signs of inhalant use can include:

Benzodiazepines and hypnotics

Benzodiazepines and sedatives include drugs used to treat various mental health disorders and physical conditions. The drugs produce a relaxing effect.

Examples of benzodiazepines and sedatives include:

Signs of benzodiazepines and hypnotics use can include:

Often, multiple factors can contribute to a person developing SUD.

Some people may have a genetic predisposition to SUD. A 2019 study identified genes associated with an increased likelihood of cannabis misuse.

Other risk factors that may cause SUD include:

  • social and peer pressure
  • aggressive behavior in childhood
  • parents or family members who misuse drugs or alcohol
  • use of drugs at a young age
  • how a drug is taken (for example, smoking or injecting increases potential for addiction)
  • lack of parental supervision
  • drug experimentation
  • poverty

Learn more about risk factors for SUD.

In many instances, SUD occurs alongside another mental health condition. When this happens, experts call it a dual diagnosis.

In the United States, about 17 million people had both an SUD and a mental health disorder in 2020.

Some people may use substances to help them cope with the symptoms of their mental health condition.

Commonly co-occurring mental health conditions include:

Healthcare professionals may perform a medical exam and take a medical history when diagnosing an SUD.

A healthcare professional may screen for psychiatric symptoms to rule out other disorders. They may also complete a substance use history.

For a diagnosis of SUD, a person must meet a minimum of 2 out of 11 criteria from the DSM-5-TR over the course of 1 year.

The DSM-TR categorizes the 11 criteria into four areas, including:

  • risky use
  • physical dependence
  • impaired control
  • social problems

Learn more about diagnosing addiction.

Healthcare professionals take an individualized approach to treating SUD.

Treatment may vary based on:

  • the substance used
  • severity of symptoms
  • any co-occurring conditions
  • the person’s preferences

Both inpatient and outpatient treatments are available. Treatment options for SUD include:

Learn more about treatment for addiction.

Help and support are available for people with SUD.

People can speak with a primary care doctor if they experience SUD symptoms or if they are concerned about a loved one who may have an SUD. In addition, local hospitals also have resources.

The following organizations can also provide support:

If someone has symptoms of an SUD, they can talk with their healthcare professional.

People may feel that a substance is adversely affecting their lives and relationships, or that they have trouble stopping use. Reaching out to a doctor can be the first step to recovery. Getting treatment can help prevent long-term negative health effects from SUD.

SUD is a health condition that leads to a strong desire to use a substance even though it may have adverse effects on a person’s life. People with SUD may use illegal or legal drugs, including prescription medications.

Symptoms may vary in severity. But often, SUD affects all areas of a person’s life. Treatment is available, such as medication to manage withdrawal side effects, long-term medications, counseling, and support groups.