Skip to main content

Verified by Psychology Today

Co-occurring disorder refers to having a co-existing mental illness and substance use disorder. While commonly used to refer to the combination of substance use and mental disorders, the term can also refer to other combinations of disorders, such as a mental disorder and an intellectual disability. (The terms dual disorder and dual diagnosis were previously used to describe the same condition.)

When a substance use disorder and a psychiatric disorder co-occur, they may differ in severity, and the severity of each can change over time. Compared to individuals who have a single disorder, those with a combination of disorders may experience more severe medical and mental health challenges and may also require longer periods of treatment.


The symptoms of co-occurring disorders include those associated with the particular substance use problem and mental health condition affecting an individual. People with co-occurring disorders are at high risk for additional problems such as symptomatic relapses, hospitalizations, financial challenges, social isolation, family problems, homelessness, sexual and physical victimization, incarceration, and serious medical illnesses.

What are examples of co-occurring disorders?

Mental health conditions that commonly co-occur with substance use disorders include anxiety disorders, depressive disorders, ADHD, bipolar disorder, schizophrenia, and personality disorders, according to the National Institute of Mental Health.

What are the symptoms of substance use disorder?

In the DSM-5, substance use disorders are defined by the class of drug used, including alcohol, caffeine, cannabis, hallucinogens, inhalants, opioids, sedatives, stimulants, and tobacco. These disorders share the defining features of addiction, such as continuing to seek the substance despite harmful consequences, neglecting normal activities, and devoting excessive time to obtaining the substance, as well as cravings, tolerance, and withdrawal.

For more, see Addiction.

article continues after advertisement

Mental health and substance use disorders result from a combination of factors. Certain people have a high genetic risk for such disorders, but one's environment can also contribute to their development.

According to the DSM-5, an increased risk of alcohol use disorder, for example, is associated with conditions including bipolar disorders, schizophrenia, and antisocial personality disorder, and alcohol use disorder may also be related to certain anxiety and depressive disorders. Other substance-related disorders also commonly co-occur with distinct psychiatric conditions. As in the case of opioid use disorder and depressive disorders, it is possible that a substance use problem leads to the development of other mental health challenges or that it worsens a preexisting disorder.

How common are co-occurring disorders?

People with mental health disorders are more likely to have a substance use disorder than those who do not. Roughly half of individuals who have either a mental illness or a substance use disorder will have the other at some point in their lives, according to the National Institute on Drug Abuse.

Which develops first: addiction or mental illness?

There are many pathways to co-occurring disorders. People with mental illness often turn to drugs or alcohol to self-medicate their anxiety, depression, or PTSD, which can then turn into an addiction. For others, chronic substance use and the problems that follow may lead to depression, anxiety, and other conditions. Both disorders can also exist without causing the other, due to underlying genetic or environmental factors.


To provide appropriate treatment for co-occurring disorders, the Substance Abuse and Mental Health Services Administration (SAMHSA) recommends an integrated treatment approach. Integrated treatment involves coordinating substance abuse and mental health interventions, rather than treating each disorder separately without consideration for the other.

Integrated treatment often involves forms of behavioral treatment, such as cognitive-behavioral therapy or dialectical behavior therapy, that can help improve coping skills and reduce maladaptive behaviors. These may be used in combination with medication. Treatment may also entail collaboration between clinicians and organizations that offer support handling issues related to housing, health, and work.

As a part of programs that treat co-occurring disorders, psychoeducational classes can help increase awareness of the symptoms of disorders and the relationship between mental disorders and substance abuse. Relapse-prevention education can help clients become aware of cues that make them more likely to abuse substances and help them develop alternative responses.

Dual-recovery groups located on treatment sites or offsite can also play a role in recovery by offering a supportive forum for the discussion of psychiatric symptoms, medication, substance-related impulses, and coping strategies.

Find a treatment center here.

What is integrated treatment?

Substance use disorders and mental illnesses were historically treated separately. For example, a treatment center might help a patient stop drinking and only then address the person’s PTSD symptoms. Integrated treatment for co-occurring disorders addresses both experiences, and the ways they overlap from the beginning of the treatment process (or immediately following detox or stabilization). Addiction specialists are trained to screen, recognize, and treat mental health conditions, and mental health professionals are trained to ask about substance use.

Why is integrated treatment important?

Integrated treatment is important because it is more effective than treating conditions in isolation. For example, the presence of depression dramatically increases the chances of relapse in the first year of recovery from alcohol addiction. Addressing mental health conditions and other underlying challenges is crucial for long-term success.

For example, one family has told the story of their son, who became addicted to opioids after sports-related shoulder surgery. He began using other substances, such as Xanax and marijuana, and anxiety and depression followed soon after. His parents asked treatment centers to address his mental health but found the treatment landscape to be siloed, disjointed, and ill-equipped to treat mental illness.

Center for Substance Abuse Treatment
Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition
National Institute on Drug Abuse
Office for Treatment Improvement, Alcohol, Drug Abuse, and Mental Health Administration
Substance Abuse and Mental Health Services Administration
Last updated: 07/22/2021