Substance use disorder (SUD) is a treatable mental disorder that affects a person’s brain and behavior, leading to their inability to control their use of substances like legal or illegal drugs, alcohol, or medications. Symptoms can be moderate to severe, with addiction being the most severe form of SUD.

People with a SUD may also have other mental health disorders, and people with mental health disorders may also struggle with substance use. These other mental health disorders can include anxiety disorders, depression, attention-deficit hyperactivity disorder (ADHD), bipolar disorder, personality disorders, and schizophrenia, among others. 

Though people might have both a SUD and a mental disorder, 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, meaning 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.

Comorbidity describes two or more disorders or illnesses occurring in the same person. They can occur at the same time or one after the other. Comorbidity also implies interactions between the illnesses that can worsen the course of both.

Yes. Addiction changes the brain in fundamental ways, changing a person’s normal needs and desires and replacing them with new priorities connected with seeking and using the drug. This results in compulsive behaviors that weaken the ability to control impulses, despite the negative consequences, and are similar to hallmarks of other mental illnesses.

Many people who have a substance use disorder also develop other mental illnesses, just as many people who are diagnosed with mental illness are often diagnosed with a substance use disorder. For example, about half of people who experience a mental illness will also experience a substance use disorder at some point in their lives and vice versa. Few studies have been done on comorbidity in children, but those that have been conducted suggest that youth with substance use disorders also have high rates of co-occurring mental illness, such as depression and anxiety.

Although substance use disorders commonly occur with other mental illnesses, this does not mean that one caused the other, even if one appeared first. In fact, establishing which came first or why can be difficult. However, research suggests three possibilities for this common co-occurrence:

• Common risk factors can contribute to both mental illness and substance use disorders. Research suggests that there are many genes that can contribute to the risk of developing both a substance use disorder and a mental illness. For example, some people have a specific gene that can make them at increased risk of mental illness as an adult, if they frequently used marijuana as a child. A gene can also influence how a person responds to a drug – whether or not using the drug makes them feel good. Environmental factors, such as stress or trauma, can cause genetic changes that are passed down through generations and may contribute to the development of mental illnesses or a substance use disorder.
• Mental illnesses can contribute to drug use and substance use disorders. Some mental health conditions have been identified as risk factors for developing a substance use disorder. For example, some research suggests that people with mental illness may use drugs or alcohol as a form of self-medication. Although some drugs may help with mental illness symptoms, sometimes this can also make the symptoms worse. Additionally, when a person develops a mental illness, brain changes may enhance the rewarding effects of substances, predisposing the person to continue using the substance.
• Substance use and addiction can contribute to the development of mental illness. Substance use may change the brain in ways that make a person more likely to develop a mental illness.

When someone has a SUD and another mental health disorder, it is usually better to treat them at the same time rather than separately. People who need help for a SUD and other mental disorders should see a health care provider for each disorder. It can be challenging to make an accurate diagnosis because some symptoms are the same for both disorders, so the provider should use comprehensive assessment tools to reduce the chance of a missed diagnosis and provide the right treatment.

It also is essential that the provider tailor treatment, which may include behavioral therapies and medications, to an individual’s specific combination of disorders and symptoms. It should also take into account 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:

• Cognitive behavioral therapy (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) 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 (such as suicide attempts, thoughts, or urges; self-harm; and drug use), and improve relationships.
• Assertive community treatment (ACT) is a form of community-based mental health care that emphasizes outreach to the community and an individualized treatment approach.
• Therapeutic communities (TC) 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) principles encourage healthy behaviors by offering vouchers or rewards for desired behaviors.

Behavioral therapies for children and adolescents

Some effective behavioral treatments for children and adolescents include:

• Brief strategic family therapy (BSFT) therapy targets family interactions thought to maintain or worsen adolescent SUDs and other co-occurring problem behaviors.
• Multidimensional family therapy (MDFT) works with the whole family to simultaneously address multiple and interacting adolescent problem behaviors, such as substance use, mental disorders, school problems, delinquency, and others.
• Multisystemic therapy (MST) targets key factors associated with serious antisocial behavior in children and adolescents with SUDs.

Medications

There are effective medications that treat opioid, alcohol, and nicotine addiction and lessen the symptoms of many other mental disorders. Some medications may be useful in treating multiple disorders. 

Mental health and substance use disorders affect people from all walks of life and all age groups. These illnesses are common, recurrent, and often serious, but they are treatable and many people do recover. Mental disorders involve changes in thinking, mood, and/or behavior. These disorders can affect how we relate to others and make choices. Reaching a level that can be formally diagnosed often depends on a reduction in a person’s ability to function as a result of the disorder. For example:

• Serious mental illness is defined by someone over 18 having (within the past year) a diagnosable mental, behavior, or emotional disorder that causes serious functional impairment that substantially interferes with or limits one or more major life activities.
• For people under the age of 18, the term “Serious Emotional Disturbance” refers to a diagnosable mental, behavioral, or emotional disorder in the past year, which resulted in functional impairment that substantially interferes with or limits the child’s role or functioning in family, school, or community activities.
• Substance use disorders occur when the recurrent use of alcohol and/or drugs causes clinically significant impairment, including health problems, disability, and failure to meet major responsibilities at work, school, or home.

The coexistence of both a mental health and a substance use disorder is referred to as co-occurring disorders.

What is dual diagnosis?

A person with dual diagnosis has both a mental disorder and an alcohol or drug problem. These conditions occur together frequently. About half of people who have a mental disorder will also have a substance use disorder at some point in their lives and vice versa. The interactions of the two conditions can worsen both.

Why do substance use disorders and mental disorders occur together?

Although these problems often occur together, this does not mean that one caused the other, even if one appeared first. In fact, it can be hard to figure out which came first. Researchers think that there are three possibilities as to why they occur together:

• Common risk factors may contribute to both mental disorders and substance use disorders. These factors include genetics, stress, and trauma.
• Mental disorders can contribute to drug use and substance use disorders. For example, people with mental disorders may use drugs or alcohol to try to feel better temporarily. This is known as self-medication. Also, mental disorders may change the brain to make it more likely you will become addicted.
• Substance use and addiction can contribute to the development of a mental disorder. Substance use may change the brain in ways that make you more likely to develop a mental disorder.

What are the treatments for dual diagnosis?

Someone with a dual diagnosis must treat both conditions. For the treatment to be effective, you need to stop using alcohol or drugs. Treatments may include behavioral therapies and medicines. Also, support groups can give you emotional and social support. They are also a place where people can share tips about how to deal with day-to-day challenges.