Co-Occurring Disorders

A person with a co-occurring disorder has been diagnosed with a substance abuse disorder and another mental health disorder. Co-occurring disorders, sometimes called dual disorders, are best treated through integrated treatment that addresses both issues at the same time.

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Fast Facts: Co-Occurring Disorders

43 millionAmerican adults have some form of mental illness
10 millioncases are considered serious mental illnesses
14 millionadults with mental illness use illicit drugs
8 millionadults have a mental illness and a substance use disorder

The brain is a complicated and delicate organ. It’s not surprising that alcohol and other drugs can cause symptoms of mental illness. The substances work by changing the way the brain operates. People who use drugs feel buzzed or high because the substances affect chemicals in the brain and the way brain cells communicate with one another.

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In response to those changes, the brain adapts to the presence of alcohol and other drugs, increasing the chances that a person will develop a substance use disorder. Substance use disorders are types of mental health disorders that are more commonly called addiction.

It’s possible to have more than one mental health disorder. Substance use disorders often co-occur alongside other mental illnesses. More than half of people with substance use disorders also have a mental illness. Sometimes the mental illness comes first. In other people, substance abuse occurs first. In both situations, each disorder amplifies the symptoms of the other.

“A large number of people with substance use disorders also have some psychiatric disorders which may or may not be major,” Dr. Timothy Huckaby, medical director of Orlando Recovery Center, told “A lot of people have underlying depression or underlying anxiety.”

Other common co-occurring disorders include personality disorders, behavior disorders and psychotic disorders. With comprehensive treatment, individuals can recover from addiction and most co-occurring mental health disorders. But failing to address co-occurring disorders during addiction treatment increases the chances of relapse.

What Are Mental Health Disorders?

The phrases “mental illness,” “mental health disorder” and “mental health issue” are often used synonymously. In its diagnostics manual, the American Psychiatric Association uses the term mental disorder to define mental illnesses, but the organization also recommends using the term mental health challenge. The American Psychiatric Association defines a mental disorder as: “a syndrome characterized by clinically significant disturbance in an individual’s cognition, emotion regulation or behavior that reflects a dysfunction in the psychological, biological or developmental processes underlying mental functioning.” Diagram showing various mental health disorders that can co-occur with addiction. Some mental disorders are more common than others. Conditions such as anxiety and depressive disorders, for example, occur more frequently than schizophrenia and psychosis. Each type of mental disorder can range in severity from mild to severe.

Developmental Disorders

Mental disorders are different from developmental disabilities. Developmental disorders, such as autism spectrum disorder and learning disabilities, impair social interaction, mobility, language and self-sufficiency. Substance use disorders and other mental health disorders can co-occur alongside developmental disorders. But the term co-occurring disorder most commonly refers to substance use disorders and mental disorders.

Dual Diagnosis & Comorbidity

Dual diagnosis is an outdated term for co-occurring disorders. Both of these terms are sometimes confused with comorbid disorders. Comorbidity is a broad term used to denote the existence of multiple physical or mental diseases or disorders. Co-occurring disorders and dual diagnosis are specific to substance use disorders and other mental health conditions. stressed woman with hands over her face

Mental Disorders that Co-Occur with Substance Abuse

Any mental health disorder can co-occur alongside substance use disorders. The most common types of co-occurring disorders include mood, anxiety, psychotic, eating, personality and behavioral disorders. Each category includes numerous types of mental disorders that can range in severity.

Mood Disorders

Mood disorders are a broad category of mental disorders that includes all types of depression and bipolar disorders. They are primarily associated with chronic feelings of sadness that last longer and are more intense than normal feelings of sadness.
Examples of mood disorders include:
  • Dysthymia
  • Major Depressive disorder
  • Bipolar I disorder
Learn more about depression

Anxiety Disorders

Anxiety and fear are normal feelings, but prolonged feelings of anxiety that worsen over time may be indicative of an anxiety disorder. Some anxiety disorders disrupt normal life, making work and other activities difficult.
Examples of anxiety disorder include:
Learn more about anxiety disorders

Psychotic Disorders

Psychotic disorders usually cause two serious symptoms: delusions and hallucinations. People with psychosis are disconnected with reality and may become a danger to themselves or others.
Types of psychotic disorders include:
  • Schizophrenia
  • Schizoaffective disorder
  • Postpartum psychosis
Learn more about schizophrenia

Eating Disorders

Like substance use disorders, eating disorders are misunderstood. People with eating disorders do not choose to eat unhealthy diets. They have a serious mental illness that causes them to perform harmful eating behaviors.
Common types of eating disorders include:
Learn more about eating disorders

Personality Disorders

Personality disorders are mental illnesses associated with unhealthy thoughts and actions. They are triggered by everyday stresses or problems, and they can disrupt hobbies, work and relationships.
Types of personality disorders include:
  • Paranoid personality disorder
  • Schizoid personality disorder
  • Schizotypal personality disorder
  • Antisocial personality disorder
  • Borderline personality disorder
  • Histrionic personality disorder
  • Narcissistic personality disorder
  • Avoidant personality disorder
  • Dependent personality disorder
Symptoms of personality disorders vary widely based on the type and severity. Learn more about personality disorders

Behavioral Disorders

Behavioral disorders most commonly occur in children. Many healthy people exhibit behavior problems, such as inattention, defiance and hyperactivity. However, behavioral disorders are characterized by chronic behavior problems that last at least six months.
Common behavioral disorders include:
  • Attention-deficit/hyperactivity disorder
  • Oppositional defiant disorder
  • Conduct disorder
Learn more about ADHD

Symptoms of Co-Occurring Disorders

The physical and emotional symptoms of co-occurring disorders vary depending on your life circumstances, the type of substances you use and the type of mental illness you possess.
Social and lifestyle symptoms of co-occurring disorders include:
  • Employment and housing instability
  • Difficulty budgeting funds
  • Legal problems
  • Isolation
  • Prostitution or sexual deviance
  • Unexplained mood shifts
  • Aggressiveness
  • Hygiene and health problems
  • Difficulty focusing
  • Treatment noncompliance
  • Violent behavior
  • Suicidal ideation
The symptoms of mental health disorders are similar to the side effects of addiction. Thus, it can be difficult to determine whether a mental illness is caused by substance abuse or vice versa. Reputable addiction treatment centers screen patients for mental illnesses and develop plans for treating co-occurring disorders simultaneously. stressed woman with hands on her face

Why Substance Use and Other Mental Disorders Co-Occur

Mental health disorders increase a person’s risk of using drugs or drinking alcohol. Substance abuse also increases the risk of developing a mental illness. However, it’s difficult to prove that one causes the onset of the other. Scientists are still studying the brain to determine how mental disorders develop, but they have several theories.
“If someone drinks or uses drugs or alcohol heavily, they’re more likely to have mood problems as a result of the substance use.”
Mark Ilgen, Psychologist, University of Michigan
“There are likely to be direct links between substance use and the mental health problem,” Mark Ilgen, a psychologist and researcher at the University of Michigan, told “If someone drinks or uses drugs or alcohol heavily, they’re more likely to have mood problems as a result of the substance use. In many cases, they’re more likely to cope with those problems by using other substances. So it’s a cyclical process.” In addition to self-medication, there are several reasons people with mental illnesses are more likely to develop substance use disorders.
Risk factors for co-occurring disorders include:
Genetic predisposition
Genes may make a person more susceptible to addiction and other mental disorders.
Environmental triggers
Stress, trauma and other events can cause mental health issues that make substances of abuse more appealing.
Involvement of similar brain regions
Brain systems responsible for functions such as reward or stress may be affected by both drug use and mental illness.
Early exposure
Being exposed to alcohol or other drugs during childhood and adolescence affects the development of the brain, making a person more susceptible to addiction and other mental illnesses.
“A lot of the risk factors for drug and alcohol problems are shared with the risk factors for mental health problems,” Ilgen said. “You may have the same set of genes underlying the psychiatric and substance-related disorders. Even if one disorder isn’t directly feeding the other, you’re more likely to have both together.” Some otherwise healthy individuals develop mental health problems after abusing alcohol or other drugs. For example, alcohol can cause major depression. Long-term meth use can cause anxiety, paranoia and hallucinations.
Looking for help with your co‑occurring disorders? Take the first step today. Get Help Now
Drugs can also cause earlier onset of mental illness. For example, people with genetic risk factors for schizophrenia often develop symptoms of the mental illness earlier in life if they regularly smoke weed. In some situations, abstaining from alcohol or drug use can mitigate mental health issues. However, some substances can cause long-lasting or permanent damage, and treatment is necessary to help people cope with the symptoms of mental illness. group of purple umbrellas with one teal umbrella in the middle

Stigma and Other Issues Involving Co-Occurring Disorders

Stigma is the greatest barrier to helping individuals with mental illness. Many people mistakenly think that people with mental illness are dangerous or that people with substance use disorders have a moral failing. In fact, the majority of people with mental illness pose no threat to others. And regardless of moral beliefs, addiction is a disease that impairs a person’s health, social function and ability to control substance use.
In 2016 more than 200,000 people who had a substance use disorder or a severe mental illness experienced homelessness. depressed teens
Source: Substance Abuse and Mental Health Services Administration This misunderstanding causes feelings of shame and fear among people with co-occurring disorders. Many people isolate themselves to avoid embarrassment, or they deny that they need mental health treatment. Stigma in our society also prevents people in need from receiving help. Cultural rejection can prevent individuals with addiction from finding work, maintaining stable housing and providing for themselves. Learn more about stigma

The Criminal Justice System

The vast majority of inmates in the federal prison system have been convicted of drug-related offenses, and the criminal justice system in the United States is one of the biggest sources of addiction treatment referrals in the country. According to a 2017 report by the Bureau of Justice Statistics, a 2011–2012 national survey found that more than a third of prisoners and nearly half of jail inmates in the United States had a history of mental illness. A separate report found that 59 percent of state prisoners and 63 percent of sentenced jail inmates met the criteria for drug dependence or abuse from 2007 to 2009. Some criminal justice programs, such as drug courts, are trying to end the cycle of recidivism by providing alternatives to incarceration. Learn more about court-ordered treatment


Homeless people often have co-occurring disorders and limited or no access to health care. They may not know that they have a mental illness, and they may have a history of legal issues that makes it impossible to hold a job. More than 200,000 people who had a substance use disorder or a severe mental illness experienced homelessness in 2016, according to the Substance Abuse and Mental Health Services Administration. Learn more about substance abuse and homelessness


Approximately 50 percent of veterans who need mental health treatment seek it, and slightly more than half of those who do receive treatment get adequate care, according to the Substance Abuse and Mental Health Services Administration. An estimated 70 percent of homeless veterans also have a substance use disorder. Some veterans choose not to seek treatment because they don’t want to be treated differently by peers, and many Veterans Affairs clinics have been plagued with long wait times. Learn more about substance abuse and veterans two men hugging for support

Recognizing and Recovering from Co-Occurring Disorders

Since the 1980s, the medical community has recognized that co-occurring disorders require specialized treatment. Over the years, the experts in the medical community have used several different terms to describe individuals with co-occurring disorders.
The various terms use to describe someone with a co-occurring disorder, include:
  • Dually diagnosed patients
  • Mentally ill chemical abuser
  • Mentally ill substance abuser
  • Mentally ill substance using
  • Chemically abusing mentally ill
  • Substance abusing mentally ill
  • Dually disordered
  • Comorbid disorders
  • Individuals with co-occurring psychiatric and substance disorders
In recent years, experts have attempted to standardize the term co-occurring disorders to avoid confusion between individuals with developmental disorders and those with mental health disorders. The Substance Abuse and Mental Health Services Administration generally uses the term co-occurring disorders to refer to substance use disorders and mental disorders.
Nanci Stockwell of Advanced Recovery Systems describes why it’s important to treat co-occurring disorders and substance use disorders simultaneously.

Integrated Treatment

Comprehensive substance abuse treatment includes therapy for underlying causes of substance abuse. Detox alone isn’t sufficient. To recover from addiction, every aspect of mental illness must be addressed.

“We know that a tremendous amount of patients have significant trauma issues in their past, and we have to address them all at the same time,” Huckaby said. “It’s not like you can just go, ‘OK, we’re going to only treat this one.’ We know that’s not the way it works.

Seeking treatment for your co‑occurring disorders?Start your journey today.

“If you don’t address these other issues, when they get to an area where they’re stressed, it’s going to lead them right back to the coping skill that they used for years, which was to do drugs,” Huckaby said. “So we really have to address all these issues simultaneously.”

Comprehensive, integrated treatment plans are designed to fit each individual’s specific health needs. The frequency and intensity of treatment is based on the severity of each mental health condition.

Continuing Aftercare

The most effective treatments for addiction last at least 30 days, but long-term recovery has to include aftercare. Most people in recovery from addiction attend daily or weekly support group meetings. Many people also receive outpatient counseling on a regular basis.

Recovery from mental illness is similar. Patients should continue to attend therapy for co-occurring mental disorders after they leave rehab. If doctors recommend medications, such as antidepressants or antipsychotics, patients should continue to take them for as long as their doctor advises.

Individuals with severe mental illness may require regular counseling appointments for life, but most people with co-occurring disorders are able to attain happiness and fulfillment after achieving sobriety from alcohol or other drugs.

Medical Disclaimer: aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.

Chris Elkins, MA
Senior Content Writer,
Chris Elkins worked as a journalist for three years and was published by multiple newspapers and online publications. Since 2015, he’s written about health-related topics, interviewed addiction experts and authored stories of recovery. Chris has a master’s degree in strategic communication and a graduate certificate in health communication.
Kim Borwick, MA
Medical Reviewer
Jason Fields
Associate Medical Director, DACCO Behavioral Health

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