Substance Use Disorder (SUD)

Substance use disorder (SUD) is a complex condition that involves a problematic pattern of substance use. It can range from mild to severe (addiction). SUD is treatable. It’s important to seek help as soon as possible if you think you or your child is developing SUD.


Learn the steps of preventing relapse of substance use disorder.

What is substance use disorder?

Substance use disorder (SUD) is a mental health condition in which a person has a problematic pattern of substance use that causes distress and/or impairs their life.

SUD exists on a spectrum and may be mild, moderate or severe. It typically involves an overpowering desire to use the substance, increased tolerance to the substance and/or withdrawal symptoms when you stop taking the substance.

A person can have more than one substance use disorder at a time, such as alcohol use disorder and cocaine use disorder.

Substance use disorder can significantly impact your health, relationships and overall quality of life. It can also be life-threatening. It’s crucial to seek help as soon as you develop signs of SUD.

What are substances?

Substances are drugs that have addiction potential. They can be prescription drugs or non-medical drugs and include:

While these substances are very different from each other, they all strongly activate the reward center of your brain and produce feelings of pleasure.

These substances vary in how likely they are to lead to SUD. The likelihood is called “addiction liability,” and it depends on multiple factors, including:

  • How you take the substance (such as orally, by injection or by inhaling).
  • The rate at which the substance crosses the blood-brain barrier and triggers the reward pathway in your brain.
  • The time it takes to feel the effect of the substance.
  • The substance’s ability to induce tolerance and/or withdrawal symptoms.


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What’s the difference between substance use/misuse and substance use disorder?

Substance use/misuse refers to occasional episodes of substance use rather than chronic, habitual or patterned use.

People can use substances occasionally without developing SUD, but even a few episodes of taking certain substances can lead to tolerance and dependence. Tobacco, heroin, cocaine, alcohol, cannabis and benzodiazepines are all substances that you can develop tolerance and dependence to.

What is the difference between substance use disorder and addiction?

Substance use disorder can be mild, moderate or severe. Addiction is the most severe form of SUD. It involves continued substance use despite negative consequences. Addiction to substances happens when the reward system in your brain “takes over” and amplifies compulsive substance-seeking.

Both involve the development of physical dependence and psychological dependence.

People are psychologically dependent when a drug is so central to their thoughts, emotions and activities that the need to continue its use becomes a craving or compulsion despite negative consequences.

With physical dependence, your body has adapted to the presence of the substance, and withdrawal symptoms happen if you suddenly stop taking the drug or you take a reduced dosage.

In the past, healthcare providers, organizations and members of the public often used the terms “addiction/addict,” “abuse/abuser” and “dependence” when referring to substance use.

Mental health condition classification systems, including the Diagnostic and Statistical Manual of Mental Disorders (DSM), have become more sophisticated over time. The term “substance use disorder” allows for more clarity in diagnosis. SUD also recognizes a spectrum of problematic substance use, not just physiologic addiction.

In addition, there’s a lot of stigma and negativity associated with the terms “addiction/addict” and “abuse/abuser.” Similarly, people often use the terms “addiction” and “addict” casually to describe an affinity for a thing, place or hobby. This downplays the seriousness and complexity of true addiction and substance use disorder.


Who does substance use disorder affect?

Substance use disorder affects people of all ages, races, genders and socioeconomic levels.

In general, people assigned male at birth (AMAB) are more likely to develop SUD. Substance use/misuse is highest among people aged 18 to 25.

How common is substance use disorder?

Substance use disorder is common. Over 20 million people in the United States have at least one SUD.

About 20% of people in the U.S. who have depression or an anxiety disorder also have a substance use disorder.

Of the over 20 million people in the U.S. who have SUD:

  • 38% have a drug substance use disorder.
  • 73% have alcohol use disorder.
  • 12% have both a drug SUD and alcohol use disorder.

What is the most common substance use disorder?

Tobacco use disorder is the most common substance use disorder worldwide and in the United States.


Symptoms and Causes

What are the signs and symptoms of substance use disorder?

According to the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, the signs of substance use disorder include:

  • Taking the substance in larger amounts and for a longer amount of time than you’re meant to if it’s a prescription.
  • Having a strong desire or urge to use the substance.
  • Having unsuccessful efforts to cut down on or control substance use.
  • Spending a lot of time obtaining or using the substance or recovering from its effects.
  • Having issues fulfilling responsibilities at work, school or home due to substance use.
  • Continuing to use the substance, even when it causes problems in relationships.
  • Giving up social, occupational or recreational activities because of substance use.
  • Using substances again and again, even when it puts you in danger.
  • Continuing substance use despite an ongoing physical or psychological problem that’s likely caused or worsened by the substance.
  • Developing tolerance (need for increased amounts to get the same effect).
  • Experiencing withdrawal symptoms, which can be relieved by taking more of the substance.

Seeking medical care as soon as you have signs of substance use disorder is essential.

Other symptoms and behaviors of substance use may include:

  • Confusion.
  • Neglecting to eat.
  • Withdrawing from friends and family.
  • Sudden changes in mood and behavior.
  • Engaging in risky behaviors.
  • Hostility or denial when you’re confronted about substance use.
  • Not caring about your physical appearance as much as you used to.
  • Secretive behavior to hide substance use.
  • Using substances even when you’re alone.

How does substance use disorder develop?

The progression to a substance use disorder often follows this pattern:

  • Experimental use (or prescription use).
  • Occasional use (or using prescriptions not as directed).
  • Heavy use.
  • Substance use disorder.

This progression is complex, and several complex factors contribute to the development of substance use disorder, including:

  • The substance’s effect on your brain chemistry.
  • Genetics.
  • Mental health conditions.
  • Access and exposure to the substance.
  • Adverse childhood experiences (ACEs).

Brain chemistry

Substances affect your brain, especially the reward center of your brain.

Humans are biologically motivated to seek rewards. Often, these rewards come from healthy behaviors. When you spend time with a loved one or eat a delicious meal, your body releases a chemical called dopamine, which makes you feel pleasure. It becomes a cycle; you seek out these experiences because they reward you with good feelings.

Substances send massive surges of dopamine through your brain, too. But instead of feeling motivated to do the things you need to survive (eat, work and spend time with loved ones), such massive dopamine levels can lead to damaging changes that affect your thoughts, feelings and behavior.

This can create an unhealthy drive to seek more pleasure from the substance and less from more healthy experiences.

Over time, the substances change your brain chemistry, and you become desensitized to their effects. You then need more to produce the same effect.

For some substances, such as opioids, the withdrawal symptoms are so severe that they create significant motivation to continue using them.


Studies show that genetic factors are responsible for 40% to 60% of the vulnerability to any substance use disorder. If you have a first-degree relative (biological sibling or parent) with SUD, you’re more likely to develop it.

Scientists are working to locate specific genes that may contribute to this vulnerability. For example, they’ve found that a change in the CHRNA2 gene on chromosome 8 is associated with cannabis use disorder, including diagnosis at an earlier age.

Mental health conditions

About half of people who experience a mental health condition will also experience a substance use disorder and vice versa. This is known as a dual diagnosis. In 2020, 17 million U.S. adults had a co-occurring mental health disorder and SUD.

SUDs and other mental health conditions are caused by overlapping factors such as genetic vulnerabilities, issues with similar areas of your brain and environmental influences.

Research shows that mental illness may contribute to SUD, and SUD can contribute to the development of mental illness.

Having any of the following mental health conditions can contribute to the development of SUD:

Access and exposure

Access to substances is a particularly significant environmental risk factor. Factors that increase the extent of exposure and the opportunity for substance use include:

  • Use of substances by a member of your household.
  • Use of substances by your peers.
  • Being prescribed a drug that can be misused, such as opioids or stimulants.

Adolescents are especially at risk for developing SUD due to exposure. Adolescents who start using substances early are more likely to develop an SUD. About 70% percent of people who began using at age 13 have an SUD compared to 27% who started at age 17.

In addition, it’s more likely that someone will use substances that are legally and/or readily available (like alcohol and tobacco). This increases the risk of progression to problematic use. Opioids are another example of this — the availability and volume of prescription opioids make them easier to access.

Adverse childhood experiences (ACEs)

Adverse childhood experiences (ACEs) are stressful or traumatic events during childhood. They can include:

  • Childhood abuse and neglect.
  • Household dysfunction.
  • Witnessing domestic violence.
  • Having family members who have SUD.
  • Parental incarceration.

ACEs are strongly related to the development of a wide range of health problems throughout a person’s lifespan, including SUD. The more ACEs a child experiences, the more at risk they are for developing SUD at some point in their life.

Diagnosis and Tests

How is substance use disorder diagnosed?

A single test can’t diagnose substance use disorder. Instead, healthcare providers rely on a thorough evaluation of your medical history and behaviors surrounding substance use. They may order drug tests and evaluate prescription drug monitoring program reports.

A provider will also ask about your mental health history, as it’s common to have an SUD and a mental health condition.

According to the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5), a person must have at least two signs in the symptoms section over 12 months to be diagnosed with substance use disorder.

It’s important to remember that SUD exists on a spectrum of severity:

  • Two to three signs indicate a mild substance use disorder.
  • Four or five signs indicate a moderate substance use disorder.
  • Six or more symptoms indicate a severe substance use disorder.

Management and Treatment

What is the treatment for substance use disorder?

Effective treatments are available for substance use disorder. Treatment is highly individualized — one person may need different types of treatment at different times.

Treatment for SUD often requires continuing care to be effective, as SUD is a chronic condition with the potential for both recovery and relapse.

As people with SUD often have co-occurring mental health conditions, treating them together rather than separately is generally better.

The three main forms of treatment include:

  • Detoxification.
  • Cognitive and behavioral therapies.
  • Medication-assisted therapies.

There are also several different types of treatment settings, including:

  • Outpatient counseling.
  • Intensive outpatient treatment.
  • Inpatient treatment.
  • Long-term therapeutic communities, such as sober living communities.


In detoxification, you stop taking the substance(s), allowing them to leave your body. Depending on the severity of the SUD, the substance or an alternative may be tapered off to lessen the effects of withdrawal. It’s the first major step of treatment for SUD. You can go through detoxification in both inpatient and outpatient settings.

Cognitive and behavioral therapies

Psychotherapy (talk therapy) can help treat SUD and any other co-occurring mental health conditions. Therapy also teaches healthy coping mechanisms.

Healthcare providers may recommend cognitive and behavioral therapies alone or in combination with medications.

Some examples of effective therapies for adults with SUDs include the following:

  • Cognitive behavioral therapy (CBT): CBT is a structured, goal-oriented type of psychotherapy. A mental health professional helps you look closely at your thoughts and emotions during CBT. You’ll come to understand how your thoughts affect your actions. You can unlearn negative thoughts and behaviors through CBT and learn to adopt healthier thinking patterns and habits. For SUD, CBT also involves encouraging motivation to change and education about treatment and preventing relapse.
  • Dialectical behavior therapy (DBT): DBT is especially effective for people who have difficulty managing and regulating their emotions. DBT has proven to be effective for treating and managing various mental health conditions, including SUD.
  • Assertive community treatment (ACT): ACT provides mental health services in a community setting rather than a residential or hospital setting. ACT is highly individualized. Your treatment plan will focus on your strengths, needs and goals for the future.
  • Therapeutic communities (TCs): A TC is a long-term residential treatment that focuses on helping people with SUD develop new and healthier values and behaviors related to substance use and other co-occurring mental health conditions.
  • Contingency management (CM): CM encourages healthy behaviors by offering rewards for desired behaviors. Most commonly, the treatment provides something of monetary value to people with SUD to incentivize them not to use substances. For instance, upon a negative drug test result, you earn a chance to receive a prize or gift card.

Participating in self-help programs, like Narcotics Anonymous, can also play a significant role in SUD treatment.

These programs support behavioral modification through self-help and peer support. The underlying principle of these programs is that people with SUD must understand that they have a chronic condition that will never go away. Group therapy supports people with SUD in maintaining self-control and restraint.


Medication may be part of your treatment plan. Medications can help modify your brain chemistry to help treat certain SUDs. They can also relieve cravings and withdrawal symptoms.

Medication-assisted treatments are available for:


How can I prevent substance use disorder?

Preventing substance use and SUD starts with education. Education in schools, communities and families helps prevent using a substance or misusing a prescription medication for the first time. Other ways to prevent SUD include:

  • Following instructions for prescription medications. Don’t ever take more than instructed. Opioid use disorder, for instance, can start after just five days of misuse.
  • Never sharing your prescription medication with someone else or selling your medication. Always store it in a safe place away from children.
  • If you have leftover prescription medications (such as opioids) at the end of your treatment, find a community drug take-back program or pharmacy mail-back program to safely dispose of them.

The risk of substance use increases greatly during times of stress and change. For an adult, a divorce, loss of a job or death of a loved one may increase the risk of substance use. For a teenager, moving, family divorce or changing schools can increase their risk.

It’s important to turn to healthy coping mechanisms during these times of change, such as exercising, meditating or learning a new hobby. Consider seeing a mental health professional if you’re having issues managing your stress.

Outlook / Prognosis

What is the prognosis for substance use disorder?

The prognosis (outlook) for substance use disorder varies based on several factors, including:

  • The type and severity of the SUD.
  • The degree of dependence and withdrawal.
  • The level of commitment to abstinence.
  • Treatment time frame.
  • Genetics.
  • How you cope during stressful situations.

Substance use disorder is a lifelong disease. But people can recover from it and lead full lives. Getting help is essential to recovery. Different tools work for different people, but ongoing therapy and self-help groups such as Narcotics Anonymous help many.

SUD is a relapsing disease. People who are in recovery have a higher chance of using substances again. Recurrence can happen even years after you last took the substance.

Because of the possibility of relapse, you need ongoing treatment. Your healthcare provider should review your treatment plan with you and change it based on your changing needs.

What are the possible complications of substance use disorder?

The complications of substance use disorder are broad and may depend on the type of substance use.

Substance use disorder can impact multiple systems of your body, including your:

Specific chronic and acute complications can include:

Living With

How can I help a loved one with substance use disorder?

It can be very challenging and stressful to learn that someone you love may have substance use disorder. Here are some tips to help your loved one and yourself:

  • Speak up sooner rather than later: The earlier a person with SUD receives treatment, the better. Address your concerns and help them find treatment as soon as possible. Suggest calling a helpline, talking to a healthcare provider or mental health professional, entering a treatment program or going to a 12-step program. Offer your help and support without being judgmental.
  • Practice empathy: Even when you don’t agree with your loved one, listen thoughtfully to them. The more your loved one feels heard, the more they’ll see you as someone they can trust.
  • Be patient: Don’t expect a single conversation or action to fix your loved one’s substance use. SUD is a complex chronic condition, and there’s no quick fix to overcoming it.
  • Take care of yourself: The friends and family members of people with SUD often experience stress, depression, grief and isolation. It’s important to take care of your mental health and seek help if you’re experiencing these symptoms. Consider joining a support group or organization in your community.

When should I see my healthcare provider?

If you’re currently taking a prescription drug and are concerned you may be developing a dependence, talk to your healthcare provider immediately.

If you think your child may be using substances, get them help as soon as possible.

A note from Cleveland Clinic

Substance use disorder is a complex mental health and brain condition. Substances — such as alcohol, stimulants and opioids — affect your brain, including your decision-making ability. These changes make it hard to stop taking the substance, even if you want to. If you or a loved one has substance use disorder, talk to a healthcare provider as soon as possible. A trained provider can help guide you to the treatment you need.

Medically Reviewed

Last reviewed on 10/20/2022.

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