Substance Use Disorder (SUD)

Substance use disorder (SUD) is a multifaceted condition characterized by problematic substance use patterns. Its severity can vary from mild to severe, often progressing to addiction. Fortunately, SUD is a treatable condition, and it’s crucial to seek assistance promptly if you suspect that you or your child may be developing it.

What is substance use disorder?

Substance use disorder (SUD) is a mental health condition characterized by a problematic pattern of substance use that results in distress and/or impairment in one’s life.

SUD spans a spectrum of severity, ranging from mild to moderate to severe. It typically involves an overwhelming urge to consume the substance, an increased tolerance to it, and the experience of withdrawal symptoms upon cessation.

Individuals may simultaneously experience multiple substance use disorders, such as alcohol use disorder and cocaine use disorder.

Substance use disorder can have profound repercussions on one’s physical and mental health, interpersonal relationships, and overall quality of life. In some cases, it can even be life-threatening. It is of utmost importance to seek assistance promptly upon recognizing signs of SUD.

What are substances?

Substances are drugs with the potential for addiction, which can be categorized as either prescription medications or non-medical drugs. They encompass a wide range of substances, including:

  1. Alcohol
  2. Caffeine
  3. Cannabis (marijuana)
  4. Hallucinogens like PCP and LSD
  5. Hypnotics, sedatives, and anxiolytics (anti-anxiety drugs), such as sleeping pills, benzodiazepines, and barbiturates
  6. Inhalants, such as paint thinners, aerosol sprays, gases, and nitrites (poppers)
  7. Prescription and non-prescription opioids like codeine, oxycodone, and heroin
  8. Prescription and non-prescription stimulants, including Adderall®, cocaine, and methamphetamine
  9. Tobacco/nicotine, such as cigarettes and electronic cigarettes (e-cigarettes or vaping)

Despite their differences, all these substances strongly activate the brain’s reward center, eliciting feelings of pleasure.

These substances also vary in their likelihood to lead to Substance Use Disorder (SUD), which is referred to as their “addiction liability.” This propensity is influenced by various factors, including:

  1. How the substance is administered (e.g., orally, injection, or inhalation)
  2. The speed at which the substance crosses the blood-brain barrier and triggers the brain’s reward pathway
  3. The time it takes to experience the substance’s effects
  4. The substance’s capacity to induce tolerance and withdrawal symptoms

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

Substance use/misuse entails occasional instances of substance use rather than chronic, habitual, or patterned consumption. It’s possible for individuals to use substances occasionally without developing SUD, but even a few episodes of certain substance use can lead to tolerance and dependence. Substances such as tobacco, heroin, cocaine, alcohol, cannabis, and benzodiazepines are known to lead to tolerance and dependence.

How does substance use disorder differ from addiction?

Substance use disorder can manifest as mild, moderate, or severe, with addiction representing the most severe form of SUD. Addiction involves persistent substance use despite adverse consequences. It occurs when the brain’s reward system becomes dominant, amplifying compulsive substance-seeking behavior.

Both substance use disorder and addiction entail the development of physical and psychological dependence. Psychological dependence arises when a drug becomes so central to an individual’s thoughts, emotions, and activities that they experience cravings or compulsions to use it despite negative consequences. Physical dependence occurs when the body adapts to the presence of the substance, leading to withdrawal symptoms when the drug is suddenly discontinued or its dosage reduced.

In the past, healthcare professionals, organizations, and the general public commonly used terms like “addiction/addict,” “abuse/abuser,” and “dependence” when discussing substance use. However, mental health classification systems, such as the Diagnostic and Statistical Manual of Mental Disorders (DSM), have evolved to offer greater precision in diagnosis. The term “substance use disorder” provides clarity in diagnosing and acknowledges a spectrum of problematic substance use, encompassing more than just physiological addiction.

Furthermore, there is significant stigma and negativity associated with the terms “addiction/addict” and “abuse/abuser.” These terms are sometimes used casually to describe an affinity for non-substance-related things, places, or hobbies, which can trivialize the seriousness and complexity of true addiction and substance use disorder.

Who is affected by substance use disorder?

Substance use disorder affects individuals of all ages, ethnicities, genders, and socioeconomic backgrounds.

In general, those assigned male at birth (AMAB) tend to have a higher likelihood of developing SUD. Substance use or misuse is most prevalent among individuals aged 18 to 25.

How common is substance use disorder?

Substance use disorder is a prevalent issue. In the United States alone, over 20 million people have been diagnosed with at least one form of SUD.

Approximately 20% of individuals in the U.S. who experience depression or an anxiety disorder also concurrently grapple with a substance use disorder.

Of the 20 million-plus individuals in the U.S. with SUD:

  • 38% have a substance use disorder related to drugs.
  • 73% have alcohol use disorder.
  • 12% experience both a drug-related SUD and alcohol use disorder.

What is the most prevalent form of substance use disorder?

Tobacco use disorder stands as the most common type of substance use disorder, both globally and in the United States.

Symptoms and Causes

What are the indications and manifestations of substance use disorder?

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

  1. Consuming the substance in quantities and durations exceeding prescribed limits (if it’s a prescription drug).
  2. Experiencing a strong urge or craving to use the substance.
  3. Unsuccessful attempts to curtail or manage substance use.
  4. Devoting substantial time to acquiring, using, or recovering from the effects of the substance.
  5. Failing to meet work, school, or home responsibilities due to substance use.
  6. Continuing substance use despite its adverse impact on relationships.
  7. Ceasing participation in social, occupational, or recreational activities because of substance use.
  8. Repeatedly using substances even in situations that pose risks.
  9. Persisting with substance use despite ongoing physical or psychological problems attributable to the substance.
  10. Developing tolerance, necessitating increased amounts to achieve the same effect.
  11. Experiencing withdrawal symptoms, which can be alleviated by consuming more of the substance.

It is essential to seek medical attention as soon as signs of substance use disorder become apparent.

Additional symptoms and behaviors related to substance use may include:

  • Confusion.
  • Neglecting dietary habits.
  • Social withdrawal from friends and family.
  • Abrupt shifts in mood and behavior.
  • Engaging in hazardous activities.
  • Demonstrating hostility or denial when confronted about substance use.
  • Reduced concern for physical appearance.
  • Concealing substance use through secretive behavior.
  • Using substances even when alone.

How does substance use disorder develop?

The progression toward substance use disorder typically follows this pattern:

  1. Experimental use (or prescription use).
  2. Occasional use (or non-prescribed use of medications).
  3. Regular, heavy use.
  4. Development of substance use disorder.

This progression is intricate, influenced by various complex factors, including:

  • The impact of the substance on brain chemistry.
  • Genetic predispositions.
  • Coexisting mental health conditions.
  • Accessibility and exposure to the substance.
  • Adverse childhood experiences (ACEs).

Brain Chemistry:

Substances exert a significant impact on your brain, particularly on the brain’s reward center. Humans possess an inherent biological drive to seek rewards, which typically arise from healthy behaviors. Engaging in activities like spending time with loved ones or enjoying a delicious meal triggers the release of dopamine, a chemical that elicits feelings of pleasure. This creates a positive feedback loop, encouraging individuals to seek out these experiences due to the rewarding sensations they provide.

Substances, however, cause substantial surges of dopamine in the brain. Instead of motivating individuals to engage in essential survival activities like eating, working, and socializing, these elevated dopamine levels can lead to detrimental changes that affect thoughts, emotions, and behavior. This can result in an unhealthy compulsion to seek pleasure primarily through substances rather than more wholesome experiences.

Over time, substances alter brain chemistry, leading to desensitization to their effects, which necessitates higher doses to achieve the same effect. In certain cases, such as opioids, withdrawal symptoms can be so severe that they compel continued substance use.


Research indicates that genetic factors contribute to 40% to 60% of an individual’s susceptibility to any substance use disorder. Having a first-degree relative (such as a biological sibling or parent) with SUD increases one’s likelihood of developing the disorder.

Scientists are actively investigating specific genes that may contribute to this vulnerability. For instance, they have identified a change in the CHRNA2 gene on chromosome 8 associated with cannabis use disorder, including an earlier onset of diagnosis.

Mental Health Conditions:

Approximately half of individuals experiencing a mental health condition will also encounter a substance use disorder, and vice versa. This co-occurrence is known as a dual diagnosis. In 2020, 17 million U.S. adults had both a co-occurring mental health disorder and SUD.

SUDs and other mental health conditions share overlapping factors, such as genetic predispositions, involvement of similar brain regions, and environmental influences. Research suggests that mental illness can contribute to the development of SUD, and conversely, SUD can lead to the emergence of mental illness.

Several mental health conditions can contribute to the development of SUD, including:

  • Attention-deficit/hyperactivity disorder (ADHD)
  • Bipolar disorder
  • Borderline personality disorder
  • Depression
  • Generalized anxiety disorder
  • Panic disorder
  • Post-traumatic stress disorder (PTSD)

Access and Exposure:

Environmental factors, particularly access to substances, play a significant role in substance use risk. Factors that increase exposure and the opportunity for substance use include:

  • Household members using substances.
  • Peer group involvement in substance use.
  • Prescription of drugs with potential for misuse, such as opioids or stimulants.

Adolescents are especially vulnerable to SUD development due to increased exposure. Those who initiate substance use at a young age are more likely to develop an SUD. Approximately 70% of individuals who start using substances at age 13 develop an SUD, compared to 27% who begin at age 17.

Furthermore, the legality and ready availability of substances, such as alcohol and tobacco, influence the likelihood of progression to problematic use. For example, opioids are more accessible due to the availability and volume of prescription opioids.

Adverse Childhood Experiences (ACEs):

Adverse childhood experiences (ACEs) encompass stressful or traumatic events during childhood, including:

  • Childhood abuse and neglect
  • Household dysfunction
  • Witnessing domestic violence
  • Family members with SUD
  • Parental incarceration

ACEs strongly correlate with the development of various health problems throughout a person’s life, including SUD. The greater the number of ACEs a child experiences, the higher their risk of developing SUD at some point in life.

Diagnosis and Tests:

Diagnosing substance use disorder requires a comprehensive evaluation rather than a single test. Healthcare providers rely on a thorough assessment of medical history and behaviors related to substance use. This may involve drug tests and an examination of prescription drug monitoring program reports.

Additionally, providers inquire about the individual’s mental health history, as co-occurring mental health conditions are common in individuals with SUD.

According to the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5), a person must exhibit at least two symptoms from the symptoms section over a 12-month period to receive a substance use disorder diagnosis.

It’s important to note that SUD spans a spectrum of severity:

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

Management and Treatment:

Substance use disorder treatment is highly individualized, as different individuals may require varying forms of treatment at different times. Effective treatment often necessitates ongoing care, as SUD is a chronic condition with the potential for both recovery and relapse.

Given the frequent co-occurrence of mental health conditions and SUD, integrated treatment for both conditions is generally more effective.

The primary forms of treatment include:

  1. Detoxification.
  2. Cognitive and behavioral therapies.
  3. Medication-assisted therapies.

Treatment settings can vary and may include:

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


Detoxification involves discontinuing the use of substances, allowing them to naturally exit your body. Depending on the severity of the Substance Use Disorder (SUD), a substance may be gradually tapered off or replaced with alternatives to mitigate withdrawal effects. This marks the initial and crucial step in SUD treatment, and it can occur in both inpatient and outpatient settings.

Cognitive and Behavioral Therapies:

Psychotherapy, also known as talk therapy, plays a pivotal role in treating SUD and co-occurring mental health conditions. Therapy equips individuals with healthy coping mechanisms. Healthcare providers may recommend cognitive and behavioral therapies alone or in conjunction with medications.

Effective therapeutic approaches for adults with SUD include:

  1. Cognitive Behavioral Therapy (CBT): CBT is a structured, goal-oriented psychotherapy that involves examining thoughts and emotions. It helps individuals understand how their thoughts influence their actions, facilitating the unlearning of negative thought patterns and behaviors. CBT for SUD also emphasizes motivation for change and educates individuals about treatment and relapse prevention.

  2. Dialectical Behavior Therapy (DBT): DBT is particularly effective for those struggling with emotional regulation. It has demonstrated success in treating various mental health conditions, including SUD.

  3. Assertive Community Treatment (ACT): ACT provides mental health services within a community setting, focusing on personalized treatment plans tailored to individual strengths, needs, and future goals.

  4. Therapeutic Communities (TCs): TCs are long-term residential programs designed to help individuals with SUD adopt healthier values and behaviors related to substance use and co-occurring mental health conditions.

  5. Contingency Management (CM): CM reinforces positive behaviors by offering rewards for desired actions. It often provides monetary incentives to encourage individuals with SUD to abstain from substance use, such as receiving prizes or gift cards upon negative drug test results.

Participation in self-help programs like Narcotics Anonymous also plays a significant role in SUD treatment. These programs promote behavioral modification through peer support and self-help principles, recognizing that SUD is a chronic condition requiring ongoing self-control and restraint.


Medication can be a crucial component of a treatment plan, as it can help modify brain chemistry and alleviate cravings and withdrawal symptoms associated with specific SUDs. Medication-assisted treatments are available for various substances:

  • Opioids: FDA-approved medications include methadone, buprenorphine, and naltrexone for opioid use disorder.
  • Alcohol: Three FDA-approved drugs for alcohol use disorder are naltrexone, acamprosate, and disulfiram.
  • Tobacco: Nicotine replacement therapies (patch, spray, gum, lozenge) or prescribed medications like bupropion and varenicline can assist in smoking cessation.


Preventing substance use and SUD starts with education in schools, communities, and families. Education helps deter initial substance use and misuse, including the inappropriate use of prescription medications. Other preventive measures include:

  • Adhering to prescription medication instructions and never exceeding recommended doses, as opioid use disorder can develop after just five days of misuse.
  • Avoiding the sharing or selling of prescription medications and storing them safely away from children.
  • Safely disposing of leftover prescription medications, particularly opioids, through community drug take-back programs or pharmacy mail-back initiatives.

Substance use risk often escalates during periods of stress and life changes. Adults may face increased risk during events such as divorce, job loss, or the loss of a loved one, while teenagers may be more vulnerable during relocations, family divorces, or school changes. Healthy coping mechanisms, such as exercise, meditation, and new hobbies, should be sought during these transitional periods. If stress becomes unmanageable, consulting a mental health professional is advisable.

Outlook / Prognosis:

The prognosis for substance use disorder varies based on several factors, including the type and severity of the SUD, the level of dependence and withdrawal, the commitment to abstinence, the duration of treatment, genetic factors, coping mechanisms during stress, and treatment effectiveness.

Substance use disorder is a lifelong condition, but recovery and a fulfilling life are attainable outcomes. Seeking help is essential for recovery, and different approaches work for different individuals. Ongoing therapy and participation in support groups like Narcotics Anonymous are beneficial for many.

SUD is characterized by relapse potential, even years after substance use cessation. As such, continued treatment and periodic adjustment of treatment plans are necessary, with healthcare providers addressing evolving needs.

Possible Complications:

Substance use disorder can lead to a wide array of complications, varying based on the substance used. It can impact various body systems, including the nervous system (with psychiatric effects), cardiovascular system, endocrine system, immune system, and hepatic (liver) system.

Chronic and acute complications may encompass:

  • Memory loss and cognitive impairment.
  • Personality changes and mood disturbances.
  • Nerve function loss.
  • Stroke.
  • Seizures.
  • Heart failure.
  • Nasal septal perforation.
  • Respiratory depression.
  • Liver failure.
  • Specific cancers associated with particular substances, such as alcohol use disorder and various cancers.
  • Blood-borne virus infections, including hepatitis B (HBV), hepatitis C (HCV), and human immunodeficiency virus (HIV) due to shared injection equipment.
  • Overdose.
  • Coma.
  • Fatality.

Living With:

Supporting a Loved One with Substance Use Disorder:

Supporting a loved one with substance use disorder can be challenging and emotionally taxing. Here are some tips to help both your loved one and yourself in such situations:

  1. Speak Up Early: Address your concerns with your loved one as soon as possible. Encourage them to seek treatment or professional help without judgment. Suggest calling a helpline, consulting a healthcare provider or mental health professional, enrolling in a treatment program, or participating in a 12-step program. Offer your support and assistance while maintaining empathy.

  2. Practice Empathy: Even if you disagree with your loved one’s choices, actively listen to them and validate their feelings. The more they feel heard and understood, the more likely they are to trust you.

  3. Be Patient: Recognize that overcoming substance use disorder is a complex and ongoing process. There is no quick fix, and recovery may involve setbacks. Patience and understanding are crucial.

  4. Self-Care: Friends and family members of individuals with substance use disorder often experience stress, depression, grief, and isolation. It’s essential to prioritize your own mental health and seek help if you’re experiencing these symptoms. Consider joining a support group or seeking assistance from organizations in your community.

When to See a Healthcare Provider:

  • If you’re currently taking a prescription drug and have concerns about developing dependence, consult your healthcare provider promptly.
  • If you suspect that your child is using substances, seek help for them as soon as possible.

In Conclusion:

Substance use disorder is a complex mental health condition that requires early intervention and comprehensive treatment. If you or a loved one is grappling with substance use disorder, reaching out to a healthcare provider or a relevant support organization is crucial. Timely and appropriate treatment can lead to recovery and improved overall well-being. Remember that recovery is possible, and support from healthcare professionals and loved ones can make a significant difference in the journey toward sobriety and a healthier life.