Substance Use Disorder (SUD)

Most people know someone with a substance use disorder (SUD), and many know someone who has lost or nearly lost a family member as a consequence of substance misuse. Yet, at the same time, few other medical conditions are surrounded by as much shame and misunderstanding as substance use disorders.

Historically, our society has treated addiction and misuse of alcohol and drugs as symptoms of moral weakness or as a willful rejection of societal norms, and these problems have been addressed primarily through the criminal justice system.

Only about 10 percent of people with a substance use disorder receive any type of specialty treatment. Further, over 40 percent of people with a substance use disorder also have a mental health condition, yet fewer than half (48.0 percent) receive treatment for either disorder.

Many factors contribute to this “treatment gap,” including the inability to access or afford care, fear of shame and discrimination, and lack of screening for substance misuse and substance use disorders in general health care settings.

About 40 percent of individuals who know they have an alcohol or drug problem are not ready to stop using, and many others simply feel they do not have a problem or a need for treatment—which may partly be a consequence of the neurobiological changes that profoundly affect the judgment, motivation, and priorities of a person with a substance use disorder.

Criteria for Diagnosing Substance Use Disorders

  • Using in larger amounts or for longer than intended
  • Wanting to cut down or stop using, but not managing to
  • Spending a lot of time to get, use, or recover from use
  • Craving
  • Inability to manage commitments due to use
  • Continuing to use, even when it causes problems in relationships
  • Giving up important activities because of use
  • Continuing to use, even when it puts you in danger
  • Continuing to use, even when physical or psychological problems may be made worse by use
  • Increasing tolerance
  • Withdrawal symptoms


  • Fewer than 2 symptoms = no disorder
  • 2-3 = mild disorder
  • 4-5 = moderate disorder
  • 6 or more = severe disorder.

Source: American Psychiatric Association, (2013).30

Binge drinking is defined as being:

  • Men – drinking 5 or more standard alcoholic drinks
  • Women – drinking 4 or more standard alcoholic drinks

on the same occasion on at least 1 day in the past 30 days.

Categories and Examples of Substances:


  • Beer
  • Wine
  • Malt liquor
  • Distilled spirits

Illicit Drugs:

  • Cocaine, including crack
  • Heroin
  • Hallucinogens, including LSD, PCP, ecstasy, peyote, mescaline, psilocybin
  • Methamphetamines, including crystal meth
  • Marijuana, including hashish
  • Synthetic drugs, including K2, Spice, and “bath salts”

Prescription-Type Medications that are Used for Nonmedical Purposes:

  • Pain Relievers – Synthetic, semi-synthetic, and non-synthetic opioid medications, including fentanyl, codeine, oxycodone, hydrocodone, and tramadol products
  • Tranquilizers, including benzodiazepines, meprobamate products, and muscle relaxants
  • Stimulants and Methamphetamine, including amphetamine, dextroamphetamine, and phentermine products; mazindol products; and methylphenidate or dexmethylphenidate products
  • Sedatives, including temazepam, flurazepam, or triazolam and any barbiturates

Over-the-Counter Drugs and Other Substances:

  • Cough and cold medicines
  • Inhalants, including amyl nitrite, cleaning fluids, gasoline and lighter gases, anesthetics, solvents, spray paint, nitrous oxide.


Substance use disorders result from changes in the brain that can occur with repeated use of alcohol or drugs. The most severe expression of the disorder, addiction, is associated with changes in the function of brain circuits involved in pleasure (the reward system), learning, stress, decision making, and self-control.

Every substance has slightly different effects on the brain, but all addictive drugs including alcohol, opioids, and cocaine, produce a pleasurable surge of the neurotransmitter dopamine in a region of the brain called the basal ganglia. Neurotransmitters are chemicals that transmit messages between nerve cells.

This area is responsible for controlling reward and our ability to learn based on rewards. As substance use increases, these circuits adapt. They scale back their sensitivity to dopamine, leading to a reduction in a substance’s ability to produce euphoria or the “high” that comes from using it. This is known as tolerance, and it reflects the way that the brain maintains balance and adjusts to a “new normal”—the frequent presence of the substance.

However, as a result, users often increase the amount of the substance they take so that they can reach the level of high they are used to. These same circuits control our ability to take pleasure from ordinary rewards like food, sex, and social interaction, and when they are disrupted by substance use, the rest of life can feel less and less enjoyable to the user when they are not using the substance.

Repeated use of a substance “trains” the brain to associate the rewarding high with other cues in the person’s life, such as friends they drink or do drugs with, places where they use substances, and paraphernalia that accompany substance-taking. As these cues become increasingly associated with the substance, the person may find it more and more difficult not to think about using, because so many things in life are reminders of the substance.

Changes to two other brain areas, the extended amygdala and the prefrontal cortex, help explain why stopping use can be so difficult for someone with a severe substance use disorder. The extended amygdala controls our responses to stress.

If dopamine “bursts” in the reward circuitry in the basal ganglia are like a carrot that lures the brain toward rewards, “bursts” of stress neurotransmitters in the extended amygdala are like a painful stick that pushes the brain to escape unpleasant situations. Together, they control the spontaneous drives to seek pleasure and avoid pain and compel a person to action.

In substance use disorders, however, the balance between these drives shifts over time. Increasingly, people feel emotional or physical distress whenever they are not taking the substance. This distress, known as withdrawal, can become hard to bear, motivating users to escape it at all costs.

As a substance use disorder deepens in intensity, substance use is the only thing that produces relief from the bad feelings associated with withdrawal. And like a vicious cycle, relief is purchased at the cost of a deepening disorder and increased distress when not using. The person no longer takes the substance to “get high” but instead to avoid feeling low. Other priorities, including job, family, and hobbies that once produced pleasure have trouble competing with this cycle.

Healthy adults are usually able to control their impulses when necessary, because these impulses are balanced by the judgment and decision-making circuits of the prefrontal cortex. Unfortunately, these prefrontal circuits are also disrupted in substance use disorders. The result is a reduced ability to control the powerful impulses toward alcohol or drug use despite awareness that stopping is in the person’s best long-term interest.

This explains why substance use disorders are said to involve compromised self-control. It is not a complete loss of autonomy—addicted individuals are still accountable for their actions—but they are much less able to override the powerful drive to seek relief from withdrawal provided by alcohol or drugs. At every turn, people with addictions who try to quit find their resolve challenged.

Even if they can resist drug or alcohol use for a while, at some point the constant craving triggered by the many cues in their life may erode their resolve, resulting in a return to substance use, or relapse.


One of the major questions about addiction is why it takes hold only in some people. The changes in the brain associated with addiction do not progress in the same way in everyone who uses alcohol or drugs.

For a wide range of reasons that remain only partially understood, some individuals are able to use alcohol or drugs in moderation and not develop addiction or even milder substance use disorders, whereas others—between 4 and 23 percent depending on the substance—proceed readily from trying a substance to developing a substance use disorder.

Understanding the factors that raise people’s risk for substance misuse (risk factors) and those that may offer some degree of protection from these risks (protective factors) and then using this knowledge to design interventions aimed at steering people away from substance misuse are the goals of prevention science.

Although research has shown strong heritability of substance use disorder, we now know that individual, family, community, and environmental risk factors play an important role in both substance misuse and substance use disorders.

Being raised in a home in which the parents or other relatives use alcohol or drugs raises a child’s chances of trying these substances and of developing a substance use disorder. Living in neighborhoods and going to schools where alcohol and drug use are common, and associating with peers who use substances, are also risk factors.

Another important risk factor is age at first use. The earlier people try alcohol or drugs, the more likely they are to develop a substance use disorder. For instance, people who first use alcohol before age 15 are four times more likely to become addicted to alcohol at some time in their lives than are those who have their first drink at age 20 or older.

Nearly 70 percent of those who try an illicit drug before the age of 13 develop a substance use disorder in the next 7 years, compared with 27 percent of those who first try an illicit drug after the age of 17.

Although substance misuse problems can develop later in life, preventing or even just delaying young people from trying substances is important for reducing the likelihood of more serious problems later on.


Few would disagree with the notion that preventing substance use disorders from developing in the first place is ideal. Prevention programs and policies are available that have been proven to do just that. If a person does develop a substance use disorder, treatment is critical.

Prevention interventions aim to support or bolster protective factors, which give people the resources and strengths they need to avoid substance use. Having strong and positive family ties and social connections, being emotionally healthy, and having a feeling that one has control over one’s successes and failures are all protective factors.

Given the overwhelming tendency for substance use to begin in adolescence (ages 12 to 17) and peak during young adulthood, most prevention interventions have focused on teens and young adults. However, effective prevention policies and programs have been developed across the lifespan, from infancy to adulthood.

It is never too early and never too late to prevent substance misuse and substance-related problems. A growing number of interventions designed to reduce risk and enhance protective factors have been scientifically tested and shown to improve substance use and other outcomes.

These include interventions for all age groups (including early childhood), for specific ethnic and racial groups, and for groups at high risk for substance misuse, such as youth involved in the criminal justice system. These interventions may focus all individuals in a group (universal interventions) or specifically on at-risk individuals (selective interventions).

Evidence-based prevention interventions can also address a wider range of potential problems beyond just substance misuse. Alcohol and drug use among adolescents are typically part of a larger spectrum of behavioral problems, including mental disorders, risky and criminal behaviors, and difficulties in school.

Many interventions address the common underlying risk factors for these issues and show benefits across these domains, making them powerful and, in many cases, highly cost-effective investments that pay off in reduced health care, law enforcement, and other societal costs.

An intervention should be a professionally delivered program, service, or policy designed to prevent substance misuse or treat an individual’s substance use disorder. It should not be an arranged meeting or confrontation intended to persuade a friend or loved one to quit their substance misuse or enter treatment—the type of “intervention” sometimes depicted on television.

Confrontational approaches in general, though once the norm even in many behavioral treatment settings, have not been found effective and may backfire by heightening resistance and diminishing self-esteem on the part of the targeted individual.


Substance use disorders share some important characteristics with other chronic illnesses, like diabetes. Both are chronic conditions that can be effectively managed with medications and other treatments that focus on behavior and lifestyle.

As with other chronic conditions, people with substance use disorders need support through the long and often difficult process of returning to a healthy and productive life.

As with other chronic illnesses, the earlier treatment begins, the better the outcomes are likely to be.

Research on alcohol and drug use, and addiction, has led to an increase of knowledge and to one clear conclusion: Addiction to alcohol or drugs is a chronic but treatable brain disease that requires medical intervention, not moral judgment.

Healthcare systems have not given the same level of attention to substance use disorders as it has to other health concerns that affect similar numbers of people. Substance use disorder treatment remains largely segregated from the rest of healthcare and serves only a fraction of those in need of treatment.

Treatment for substance use disorders can take many different forms and may be delivered in a range of settings varying in intensity. In all cases, though, the goals of treatment for substance use disorders are similar to treatment for any medical condition: to reduce the major symptoms of the illness and return the patient to a state of full functioning.

Ideally, services are not “one size fits all” but are tailored to the unique needs of the individual. Treatment must be provided for an adequate length of time and should address the patient’s substance use as well as related health and social consequences that could contribute to the risk of relapse, including connecting the patient to social support, housing, employment, and other wrap-around services.

Residential treatment was designed to provide a highly controlled environment with a high density of daily services. Ideally, people who receive treatment in residential settings participate in step-down services following the residential stay.

Medications are also available to help treat people addicted to alcohol or opioids. Research is underway to develop new medications to treat other substance use disorders, such as addiction to marijuana or cocaine.

The available medications do not by themselves restore the addicted brain to health, but they can support an individual’s treatment process and recovery by preventing the substance from having pleasurable effects in the brain, by causing an unpleasant reaction when the substance is used, or by controlling symptoms of withdrawal and craving.

As with other chronic, relapsing medical conditions, treatment can manage the symptoms of substance use disorders and prevent relapse. Rates of relapse following treatment for substance use disorders are comparable to those of other chronic illnesses such as diabetes, asthma, and hypertension.

However, many people seek or are referred to substance use treatment only after a crisis, such as an overdose, or through involvement with the criminal justice system. With any other health condition like heart disease, detecting problems and offering treatment only after a crisis is not considered good medicine.


Support services such as mutual aid groups, recovery housing, and recovery coaches are increasingly available to help people in the long and often difficult task of maintaining recovery after treatment.

Because the brain can take a long time to return to health following a long period of heavy substance use, risk of relapse is high at first. It can take a year of abstinence before an individual can be said to be in remission.

For people recovering from an alcohol use disorder it can take 4 to 5 years of abstinence for the risk of relapse to drop below 15 percent—the level of risk of individuals in the general population developing a substance use disorder during their lifetime.

In addition, successful recovery often involves making significant changes to one’s life to create a supportive environment that avoids substance use or misuse cues or triggers. This can involve changing jobs or housing, finding new friends who are supportive of one’s recovery, and engaging in activities that do not involve substance use.

Recovery has become an increasingly important concept for researchers and practitioners in the substance use disorder field, as well as in the community. It is central to a movement to bring greater awareness to the struggles and the successes of people fighting addiction and increase solidarity in overcoming the discrimination, shame, and misconceptions historically associated with substance use disorders.

A large body of research has clarified the biological, psychological, and social underpinnings of substance misuse and related disorders and described effective prevention, treatment, and recovery support services. Future research is needed to guide the new public health approach to substance misuse and substance use disorders.


In the past, many individuals and families have kept silent about substance-related issues because of shame, guilt, or fear of exposure or recrimination. Breaking the silence and isolation around such issues is crucial, so that individuals and families confronting substance misuse and its consequences know that they are not alone and can openly seek treatment.

Recognizing that substance use disorders are medical conditions and not moral failings can help remove negative attitudes and promote open and healthy discussion between individuals with substance use disorders and their loved ones, as well as with their health care professionals.

Overcoming the powerful drive to continue substance use can be difficult, and making the lifestyle changes necessary for successful treatment—such as changing relationships, jobs, or living environments—can be daunting.

Being compassionate and caring does not mean that you do not hold the person accountable for their actions. It means that you see the person’s behaviors in the light of a medical illness. Love and support can be offered while maintaining the boundaries that are important for your health and the health of everyone around you.

We typically show empathy when someone we know is ill, and we celebrate when people we know overcome an illness. Extending these kindnesses to people with substance use disorders and those in recovery can provide added encouragement to help them realize and maintain their recovery. It also will encourage others to seek out treatment when they need it.

Become informed, from reliable sources, about substances to which your children could be exposed, and about substance use disorders, and talk openly with your children about the risks.

Some tips to keep in mind:

  • Be a good listener
  • Set clear expectations about alcohol and drug use, including real consequences for not following family rules
  • Help your child deal with peer pressure
  • Get to know your child’s friends and their parents
  • Talk to your child early and often
  • Support your school district’s efforts to implement evidence-based prevention interventions and treatment and recovery support.


Schools represent one of the most effective channels for influencing youth substance use. Many highly effective evidence-based programs are available that provide a strong return on investment, both in the well-being of the children they reach and in reducing long-term societal costs.

Prevention programs for adolescents should target improving academic as well as social and emotional learning to address risk factors for substance misuse, such as early aggression, academic failure, and school dropout.

When combined with family-based and community programs that present consistent messages, these programs are even more powerful. Interventions that target youth who have already initiated use of alcohol or drugs should also be implemented to prevent escalation of use.

Teachers, professors, and school counselors play an obvious and central role as youth influencers, teaching students about the health consequences of substance use and misuse and about substance use disorders as medical conditions, as well as facilitating open dialogue.

They can also promote non-shaming language that underscores the medical nature of addiction—for instance avoiding terms like “abuser” or “addict” when describing people with substance use disorders.


All health care professionals including:

  • Physicians
  • Physician assistants
  • Nurses
  • Nurse practitioners
  • Dentists
  • Social workers
  • Therapists
  • Pharmacists

can play a role in addressing substance misuse and substance use disorders, not only by directly providing health care services, but also by promoting prevention strategies and supporting the infrastructure changes needed to better integrate care for substance use disorders into general health care and other treatment settings.

Moreover, although 45 percent of patients seeking treatment for substance use disorders have a co-occurring mental disorder, most specialty substance use disorder treatment programs are not part of, or even affiliated with, mental or physical health care organizations.


Health care systems can help prevent prescription drug misuse and related substance use disorders by holding staff accountable for safe prescribing of controlled substances, training staff on alternative ways of managing pain and anxiety, and increasing use of PDMPs by pharmacists, physicians, and other providers.

Effective integration of behavioral health and general health care is essential for identifying patients in need of treatment, engaging them in the appropriate level of care, and ensuring ongoing monitoring of patients with substance use disorders to reduce their risk of relapse.


Civic and advocacy groups, neighborhood associations, and community-based organizations can all play a major role in communication, education, and advocacy efforts that seek to address substance use-related health issues.

Prevention research has developed effective community-based prevention programs that reduce substance use and delinquent behavior among youth. Research shows that for each dollar invested in research-based prevention programs, up to $10 is saved in treatment for alcohol or other substance misuse-related costs.

An essential part of a comprehensive public health approach to addressing substance misuse is wider use of strategies to reduce individual and societal harms, such as overdoses, motor vehicle crashes, and the spread of infectious diseases.

The implementation of needle/syringe exchange programs, successfully reduce the spread of HIV and Hepatitis C without seeing an increase in injection drug use.


Manufacturers and sellers of alcohol, legal drugs, and related products have a role in reducing and preventing youth substance use. They can discourage the sale and promotion of alcohol and other substances to minors and support evidence based programs to prevent and reduce youth substance use.

Pharmaceutical companies and pharmacies can continue to collaborate with Government Departments to identify and implement evidence-informed solutions to the current opioid crisis. This collaboration may include:

  • Examining and revising product labeling
  • Funding continuing medical education for providers on the appropriate use of opioid medications
  • Developing abuse-deterrent formulations of opioids
  • Prioritizing development of non-opioid alternatives for pain relief
  • Conducting studies to determine the appropriate dosing of opioids in children and safe prescribing practices for both children and adults.


Coordinated federal, state, local, and tribal efforts are needed to promote a public health approach to addressing substance use, misuse, and related disorders. Widespread cultural and systemic issues need to be addressed to reduce the prevalence of substance misuse and related public health consequences.

Government agencies have a major role to play:

  • Improving public education and awareness
  • Conducting research and evaluations
  • Monitoring public health trends
  • Providing incentives, funding, and assistance to promote implementation of effective prevention, treatment, and recovery practices, policies, and programs
  • Addressing legislative and regulatory barriers
  • Improving coordination between health care, criminal justice, and social service organizations
  • Fostering collaborative initiatives with the private sector

For example, federal and state agencies can implement policies to integrate current best practices guidelines for prescribing opioids for chronic pain or mandatory use of Prescription Drug Monitoring Programs (PDMPs).

The criminal justice and juvenile justice systems can play pivotal roles in addressing substance-related health issues across the community. Less punitive, health-focused initiatives can have a critical impact on long-term outcomes.

The criminal justice system is engaged in efforts to place non-violent drug offenders in treatment instead of jail, to improve the delivery of evidence-based treatment for incarcerated persons, and to coordinate care in the community when inmates are released.

Law enforcement should work closely with citizens’ groups, prevention initiatives, treatment agencies, and recovery community organizations to create alternatives to arrest and lockup for nonviolent and substance use-related offenses.

Prevention and treatment also reduce criminal-justice-related costs, and they are much less expensive than alternatives such as incarceration. Implementation of evidence-based interventions can have a benefit of more than $58 for every dollar spent; and studies show that every dollar spent on substance use disorder treatment saves $4 in health care costs and $7 in criminal justice costs.


Scientific research should be informed by ongoing public health needs. This includes research on the basic genetic and epigenetic contributors to substance use disorders and the environmental and social factors that influence risk:

  • Basic neuroscience research on substance use-related effects and brain recovery
  • Studies adapting existing prevention programs to different populations and audiences
  • Trials of new and improved treatment approaches.

Focused research is needed to help address the significant research-to-practice gap in the implementation of evidence-based prevention and treatment interventions. Closing the gap between research discovery and clinical and community practice is both a complex challenge and an absolute necessity if we are to ensure that all populations benefit from the nation’s investments in scientific discoveries.

U.S. Department of Health and Human Services

The Surgeon General’s Report on Alcohol, Drugs, and Health

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