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What Is a Substance Use Disorder (SUD)?

Read on to learn more about the symptoms and treatment options you can receive for a substance use disorder (SUD).

Table of Contents

Clinically Reviewed By Adam Diaz, Associate Director of Clinical Services, APCC, AMFTLast reviewed: September 2026

What Is a Substance Use Disorder?

A substance use disorder (SUD) is characterized by the recurrent use of drugs or alcohol despite the negative consequences it causes to a person’s health, social life, work, and other areas of life. SUDs are a chronic, relapsing brain disease that can affect a person’s behavior, thoughts, and emotions.
A substance use disorder is the clinical term used to describe addiction to drugs or alcohol. SUDs encompass a range of addiction severity, from mild to severe, depending on the number of criteria met.1
substance use disorder

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Types of SUDs

Mild SUDs may involve two or three symptoms, moderate SUDs may involve four or five symptoms, and severe SUD(s) may involve six or more.2

Addiction is a complex and chronic brain disease that affects a person’s behavior, thoughts, and emotions in many ways. It is characterized by compulsive drug or alcohol use despite harmful consequences and the inability to stop using the substance despite efforts to quit.3

Symptoms of SUDs

SUDs are typically diagnosed when a person meets specific criteria, such as:
  • Continued use of the substance despite significant problems or consequences
  • Difficulty controlling the use of the substance
  • The development of a tolerance to the substance, meaning the person needs more of it to achieve the desired effect
  • Withdrawal symptoms when the substance is discontinued or decreased. 
  • Spending a significant amount of time obtaining, using, or recovering from the effects of the substance
  • Giving up important social, occupational, or recreational activities due to substance use
  • Using the substance in hazardous situations, such as driving under the influence.
SUDs can have severe consequences on a person’s physical and mental health, including increased risk for overdose, infections, and mental health disorders.

What Substances Are Usually Involved?

A substance use disorder can involve a wide range of substances, including;
  • Alcohol: Alcohol use disorder (AUD) is a common type of SUD that involves the excessive use of alcohol, which can lead to significant physical and psychological problems.
  • Prescription drugs: SUDs can involve using prescription drugs such as opioids, benzodiazepines, and stimulants. Prescription drug misuse can lead to addiction and overdose.
  • Illicit drugs: SUDs can involve using illegal drugs such as cocaine, heroin, methamphetamine, and marijuana. Illicit drug use can lead to addiction, health problems, and legal issues.
  • Nicotine: Nicotine addiction is a type of SUD that involves using tobacco products such as cigarettes, cigars, and chewing tobacco. 
  • Inhalants: Inhalants are another type of SUD, including paint thinners, gasoline, and aerosol sprays. Inhalant misuse can cause significant damage to the brain, heart, liver, and kidneys.
  • Other substances: SUD can involve the use of other substances, such as caffeine, hallucinogens, and steroids.
It’s important to note that any substance, whether legal or illegal, can lead to addiction if misused. The severity of SUD can vary depending on the substance, the frequency of use, and other factors.

How Does a Substance Use Disorder Develop?

Substance use disorders may develop for multiple reasons, including genetic, environmental, and personal factors. Here are some of the factors that can contribute to the development of SUD:

Genetics

Studies have shown that specific genes may increase a person’s vulnerability to addiction.

Environmental Factors

Environmental factors such as stress, trauma, and social influences can contribute to the development of SUD.

Mental Health Conditions

Mental health conditions such as depression, anxiety, and post-traumatic stress disorder (PTSD) can increase the risk of developing SUD. People may use substances to self-medicate and alleviate symptoms of these conditions.

Brain Chemistry

Substance use can alter the brain’s reward system, leading to changes in brain chemistry that can cause addiction.

Early Use

The younger a person is when they start using substances, the more likely they are to become addicted.

Trauma

Trauma, such as physical, emotional, or sexual abuse, can increase the likelihood of developing substance use disorders as individuals may turn to substances as a coping mechanism.

Social and Cultural Factors

Social and cultural factors such as peer pressure, cultural norms, and media influences can also contribute to the development of SUD.

Availability of Substances

Easy access to drugs and alcohol can increase the likelihood of substance use disorders.

Adverse Childhood Experiences (ACEs)

ACEs have been shown to increase the likelihood of an individual developing a substance use disorder later in life. These experiences may include abuse, a caregiver being reliant upon a substance themselves, or various other forms of trauma. It’s important to understand the far-reaching effects that ACEs can have on both a child and adult’s life in order to get the care and help you deserve.4
It’s important to note that the development of SUDs is complex and multifaceted, and treatment should be tailored to the individual’s needs.

What Are Treatment Options For a Substance Use Disorder?

The treatment options for individuals with a substance use disorder will depend on their specific needs and goals. Here are some standard treatment options:
  • Behavioral therapy: This aims to modify harmful behaviors and teach positive behaviors. It can also be used to address various issues, such as communication skills, social skills, and self-care skills.
  • Medication management: For individuals with co-occurring mental health conditions or other medical conditions, medication may be prescribed to manage symptoms.
  • Occupational therapy: This therapy helps individuals with disabilities learn skills to perform activities of daily living and work-related tasks.
  • Vocational training and job placement: For individuals who are able and interested in working, vocational training and job placement services can help them develop job skills and find employment.
  • Family therapy: This therapy involves the entire family and aims to improve communication, understanding, and support within the family unit.
  • Case management: Case managers can help individuals access necessary services, navigate systems, and coordinate care.
  • Support groups: Support groups can provide individuals and their families with a safe and supportive environment to discuss their experiences and receive emotional support.

Get Help at Horizon Treatment Services

If you or a loved one are struggling with the symptoms of a substance use disorder, know that you are not alone. Our caring and supportive staff is here to help you figure out the best treatment plan for your needs. We understand just how difficult SUDs can be to handle, which is why our aim is to help individuals learn about the treatment available to them and get them the care they need.

Reach Out for More Information

Reach out to Horizon Treatment Services today. Together, we can work toward creating a more understanding and helpful world for those struggling with any symptoms or stigma arising from a substance use disorder.

Resources

1 https://my.clevelandclinic.org/health/diseases/16652-drug-addiction-substance-use-disorder-sud

2 https://www.mayoclinic.org/diseases-conditions/drug-addiction/symptoms-causes/syc-20365112

3 https://mnprc.org/wp-content/uploads/2019/01/aces-behavioral-health-problems.pdf

 

Adam Diaz

Clinically Reviewed By

Adam Diaz

Associate Director of Clinical Services, APCC, AMFT

Last reviewed: September 2026

Adam Diaz is an Associate Professional Clinical Counselor and Associate Marriage and Family Therapist who brings a strong foundation in treating co-occurring disorders and a deep commitment to client-centered care. His journey with Horizon Treatment Services began as a Master of Arts counseling intern at…

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