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Co-Occurring Disorders and Substance Abuse

Written by Jonathan Strum

& Medically Reviewed by Dr. Sarah Dash, PHD

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Last Updated - 12/29/2022

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Updated 12/29/2022

Key Takeaways

  • Co-occurring disorders can occur across a range of mental disorders, such as mood or psychotic disorders, and can involve drug or alcohol misuse
  • The causes of mental illness and related substance use are diverse and can interact with one another. Genetic, individual, social and environmental factors can all contribute to co-occurring disorders.
  • People with mental illness are at increased risk of substance use disorders.
  • Compared to the general population, the risk of mortality is greater among those with a dual diagnosis.
  • Treatment for co-occurring disorders must consider the needs of the individual, be well-integrated and be provided at the same time.

Co-occurring disorders are more complex than mental illness or substance misuse on their own. For a better chance of effective treatment, both disorders must be addressed directly.

Mental illness and drug addiction are often closely. Researchers estimate that nearly 9 million U.S. adults have co-occurring mental health and substance use disorders.

Co-occurring disorders are complex, but understanding the signs and symptoms of these disorders can help doctors provide an accurate diagnosis and establish an effective treatment. There are many different types of co-occurring disorders, and each has its own risks, complications and complex treatment needs.

What Is a Co-Occurring Disorder?

A co-occurring disorder, also known as a dual diagnosis, is defined as the presence of both a mental health disorder and substance use disorder at the same time.

The term “co-occurring disorder” broadly represents many possible combinations of mental health disorders and addictions. For example, one person may abuse methamphetamine and also have symptoms of schizophrenia. Another may struggle with major depressive disorder and misuse alcohol.

Although co-occurring disorders can be diagnosed separately, the presence of multiple disorders can increase the symptoms of each. In addition, many substances have side effects that mimic symptoms of mental illness, such as delusions and hallucinations. This can make it difficult to differentiate whether symptoms are being caused by substance use or by the mental health condition. Understanding the key risk factors and most common co-occurring disorders can help support effective diagnosis and treatment.

Common Co-Occurring Disorders

It is difficult to track the exact rates of different types of co-occurring disorders, as diagnoses may include multiple substances. In addition, there are no exact patterns of use. For example, stimulants, alcohol and tobacco use may be paired with schizophrenia, but opioids and alcohol may be used in mood or personality disorders. Alcohol is widely used across many different types of mental health disorders.

Research shows that lifetime substance use disorders are linked to mood disorders, post-traumatic stress disorder, panic disorder, social phobia, and several personality disorders. While substance use may cause new mental health disorders to develop, substance use can also be a coping strategy for an existing mental illness.

Some co-occurring disorders are more common than others. The most common include mood, anxiety, personality, eating, and psychotic disorders.

Mood Disorders

Mood disorders are characterized by disturbances in a person’s mood. There are different types of mood disorders, including major depression, anxiety disorders, and bipolar disorder. The signs and symptoms of mood disorders vary based on type, but they can include loss of pleasure in usual activities, social withdrawal, extreme euphoria or recklessness.

Related Topic: Alcohol and Depression

Anxiety Disorders

Anxiety is often used as a blanket term, but there are many different anxiety disorders. For example, panic disorder, social phobia and specific phobias like claustrophobia are all considered types of anxiety disorders. The signs of anxiety disorder can include physical symptoms like sweating or shortness of breath. It can also include behaviors like avoiding anxiety-inducing situations or becoming overly dependent on a person or thing that brings comfort.

Personality Disorders

Personality disorders can cause extreme, inflexible thoughts or behavior that make it difficult to function in day-to-day life. Different personality disorders include antisocial personality disorder, borderline personality disorder, and narcissistic personality disorder. Each disorder is characterized by different features or symptoms, such as obsessions or paranoia. Personality disorder symptoms vary depending on the type, but they can involve unpredictable behavior and fearful thinking.

Eating Disorders

Eating disorders are characterized by disturbances in eating behaviors and obsessions about food, body weight, size or shape. As there are different types of eating disorders, there is no specific set of symptoms that represents all eating disorders. People with eating disorders can have a range of body shapes and sizes, and they may struggle with undereating or overeating. Others may feel out of control around food or overcompensate for energy intake. As a result, the signs of an eating disorder may not always be obvious to others.

Psychotic Disorders

Psychotic disorders sometimes called psychosis, cause people to lose touch with reality or experience unusual thoughts or perceptions. Early signs of psychosis can include a decline in performance at work or school, suspiciousness of others, decreased hygiene or inappropriate emotions. Different types of psychosis include schizophrenia, schizoaffective disorder, and delusional disorder.

Related Topic: Can alcohol cause schizophrenia?

Causes of Mental Illness

Mental health is complex, and many factors can interact with one another to increase risk. In general, a combination of genetic, social and environmental factors can contribute to the onset of a mental illness.

It is unlikely that there is a single factor or experience that will cause a mental health disorder. In many cases, a person may have a genetic or biological vulnerability to mental illness that is then aggravated by a stressful or traumatic experience. There are also individual characteristics that increase the risk of mental illness. For example, factors like personality or gender are linked with an increased risk of some mental disorders.

Importantly, mental disorders can be related to each other in complex ways. Substance use disorders and mental illnesses are often related, and they may even contribute to one another. For example, the presence of a mental disorder can lead to substance use as a coping strategy. In contrast, a substance use disorder can increase the likelihood of a mental disorder developing.

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Co-occurring Disorders and Substance Abuse

Mental health disorders and substance use disorders are serious and high-risk conditions on their own, but the dangers can be compounded when they occur together. Importantly, co-occurring disorders with substance abuse can be challenging to assess. This is because substance use can cause mental health symptoms that may or may not be present at other times.

Statistics show that people with mental illness are more likely to have a substance use disorder. Rates of dual diagnosis are estimated to be as high as 80% among those in mental health or addiction treatment.

The rates of co-occurrence differ slightly between people with alcohol use disorder and people with other substance use disorders, with rates higher among those using drugs. Given the risk of substance use and the additional challenges caused by mental illness, people with co-occurring disorders are at increased risk of mortality compared to the general population.

Dual Diagnosis Treatment

In the past, treatments for substance use disorders and mental illness were kept separate. More recently, health professionals have recognized the importance of well-integrated dual diagnosis treatment. This approach allows for an understanding of the full range of symptoms and how they are related.

Treatment for mental illness and substance abuse focuses on reducing symptoms and improving a person’s ability to function normally. Successful treatment plans for co-occurring conditions should consider both disorders as the main illness, and treatment for both should occur at the same time.

The types of treatments may vary by type of disorder, but treatment often includes a combination of therapy and medication. For example, cognitive behavioral therapy and motivational enhancement therapy can help improve patient functioning and reduce relapse. Medication may also help reduce drug cravings, minimize withdrawal symptoms or mimic the effects of the addictive substance.

Importantly, treatment must be tailored to the individual and should consider a person’s history, environment, and current motivation.

View Sources

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Balhara, Yatan Pal Singh; Prakesh, Sathya; Mahapatra, Ananya; et al. “Dual Diagnosis: Psychotic Disorders.” Indian Psychiatric Society, 2016. Accessed December 9, 2019.

Szerman, Nestor; Parro-Torres, Carlos; Didia Javier; et al. “Dual Disorders: Addiction and other Mental Disorders.” Advances in Psychiatry, July 7, 2019. Accessed December 9, 2019.

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