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National Suicide Prevention Lifeline

988  or 1-800-273-TALK (8255)

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'START' 741-741

substance use disorders

What is it?

What Causes it?

Signs / Symptoms

Treatment / Therapies

A Substance Use Disorder (SUD) is a mental disorder that affects a person's brain and behavior, leading to a person's inability to control their use of substances such as legal or illegal drugs, alcohol, or medications. Symptoms can range from moderate to severe, with addiction being the most severe form of SUDs. Researchers have found that about half of individuals who experience a SUD during their lives will also experience a co-occurring mental disorder and vice versa. Co-occurring disorders can include anxiety disorders, depression, Attention-Deficit Hyperactivity Disorder (ADHD), Bipolar Disorder, personality disorders, and Schizophrenia, among others.  

Source: National Institute of Mental Health (NIMH), U.S. Department of Health & Human Services

While SUDs and other mental disorders commonly co-occur, that does not mean that one caused the other. Research suggests three possibilities that could explain why SUDs and other mental disorders may occur together:


Common risk factors can contribute to both SUDs and other mental disorders. Both SUDs and other mental disorders can run in families, suggesting that certain genes may be a risk factor. Environmental factors, such as stress or trauma, can cause genetic changes that are passed down through generations and may contribute to the development of a mental disorder or a substance use disorder.


Mental disorders can contribute to substance use and SUDs. Studies found that people with a mental disorder, such as anxiety, depression, or Post-Traumatic Stress Disorder (PTSD), may use drugs or alcohol as a form of self-medication. However, although some drugs may temporarily help with some symptoms of mental disorders, they may make the symptoms worse over time. Additionally, brain changes in people with mental disorders may enhance the rewarding effects of substances, making it more likely they will continue to use the substance.

Substance use and SUDs can contribute to the development of other mental disorders. Substance use may trigger changes in brain structure and function that make a person more likely to develop a mental disorder.

Source: National Institute of Mental Health (NIMH), U.S. Department of Health & Human Services

Substance use disorders can refer to substance abuse or substance dependence. Symptoms of substance use disorders may include:

  • Behavioral changes, such as:

    • drop in attendance and performance at work or school

    • frequently getting into trouble (fights, accidents, illegal activities)

    • using substances in physically hazardous situations such as while driving or operating a machine

    • engaging in secretive or suspicious behaviors

    • changes in appetite or sleep patterns

    • unexplained change in personality or attitude

    • sudden mood swings, irritability, or angry outbursts

    • periods of unusual hyperactivity, agitation, or giddiness

    • lack of motivation

    • appearing fearful, anxious, or paranoid, with no reason


  • Physical changes, such as:

    • bloodshot eyes and abnormally sized pupils

    • sudden weight loss or weight gain

    • deterioration of physical appearance

    • unusual smells on breath, body, or clothing

    • tremors, slurred speech, or impaired coordination


  • Social changes, such as:

    • sudden change in friends, favorite hangouts, and hobbies

    • legal problems related to substance use

    • unexplained need for money or financial problems

    • using substances even though it causes problems in relationships

Source: National Institute of Mental Health (NIMH), American Psychiatric Association (APA), MayoClinic, National Eating Disorders Association (NEDA)

Generally, it is better to treat the SUD and the co-occurring mental disorders together rather than separately. Thus, people seeking help for a SUD and other mental disorders need to be evaluated by a health care provider for each disorder. Because it can be challenging to make an accurate diagnosis due to overlapping symptoms, the provider should use comprehensive assessment tools to reduce the chance of a missed diagnosis and provide targeted treatment.                                          


It is essential that treatment, which may include behavioral therapies and medications, be tailored to an individual’s specific combination of disorders and symptoms, the person’s age, the misused substance, and the specific mental disorder(s). Talk to your health care provider to determine what treatment may be best for you and give the treatment time to work.               


Behavioral Therapies:

Research has found several behavioral therapies that have promise for treating individuals with co-occurring substance use and mental disorders. Health care providers may recommend behavioral therapies alone or in combination with medications.

Some examples of effective behavioral therapies for adults with SUDs and different co-occurring mental disorders include the following:


  • Cognitive Behavioral Therapy (CBT): CBT is a type of talk therapy aimed at helping people learn how to cope with difficult situations by challenging irrational thoughts and changing behaviors.

  • Dialectical Behavior Therapy (DBT): DBT uses concepts of mindfulness and acceptance or being aware of and attentive to the current situation and emotional state. DBT also teaches skills that can help control intense emotions, reduce self-destructive behaviors (e.g., suicide attempts, thoughts, or urges; self-harm; and drug use), and improve relationships.

  • Assertive Community Treatment (ACT): This is a form of community-based mental health care that emphasizes outreach to the community and an individualized treatment approach.

  • Therapeutic Communities (TC): TCs are a common form of long-term residential treatment that focuses on helping people develop new and healthier values, attitudes, and behaviors.

  • Contingency Management (CM): CM principles encourage healthy behaviors by offering vouchers or rewards for desired behaviors.  

  • Medications: Effective medications exist for treating opioid, alcohol, and nicotine addiction and lessening the symptoms of many other mental disorders. Some medications may be useful in treating multiple disorders. Talk to your doctor or mental health professional to discuss possible options & side effects.

Source: National Institute of Mental Health (NIMH), U.S. Department of Health & Human Services

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