April 16, 2020

Dual Diagnosis: The Connection Between Mental Health & Addiction

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Table of Contents

Medicially Reviewed By:
Dr. Priya Chaudhri
credentials here

The National Alliance on Mental Illness defines mental illness as a condition that affects an individual’s thoughts, feelings or mood and which may impact the ability to relate to other people.1 Genetics, environment and lifestyle are all factors that determine whether someone will develop a mental disorder.

The 2014 National Survey on Drug Use and Health revealed that more than 43 million Americans over the age of 18 had some form of mental illness, and over 20 million suffered from a substance use disorder.2 Nearly eight million people had both a mental disorder and a substance use disorder, known as a dual diagnosis or co-occurring disorders.

The Prevalence of Co-Occurring Disorders

People who have a mood or anxiety disorder are twice as likely as the general population to suffer from a substance use disorder.3 Conversely, people who have a substance use disorder are twice as likely as the general population to suffer from a mood or anxiety disorder.

People who have a mood or anxiety disorder are twice as likely as the general population to suffer from a substance use disorder.

All told, around a third of people who have any type of mental condition and half of those with a serious mental illness also have a substance use disorder. Around a third of people who abuse alcohol and more than half of those who abuse drugs also report having a mental illness.4

Why Addiction and Mental Illness Commonly Co-Occur

Three scenarios help explain why so many people suffer from both a mental illness and an addiction.5

  • Abusing drugs can cause the onset of a mental illness or worsen an existing mental condition.
  • People who have a mental illness may self-medicate with drugs or alcohol to alleviate certain symptoms, and this can lead to addiction.
  • Overlapping factors for both substance use disorders and other mental illnesses can leave certain individuals more vulnerable to developing co-occurring disorders.

Overlapping Factors for Mental Illness & Addiction

Overlapping genetic vulnerabilities, the involvement of similar brain regions and environmental considerations are the three most prevalent factors that influence whether someone will develop a co-occurring disorder.

Overlapping Genetic Vulnerabilities

Scientists have linked several areas of the human genome to an increased risk of both substance use disorders and mental illness. Between 40 and 60 percent of your risk of developing an addiction is genetic.

A gene may impact your risk directly, such as by controlling how you metabolize a certain substance, or it may act indirectly, such as by determining whether you tend to engage in risk-taking behaviors. Likewise, these and other genetic factors can help determine whether you’ll develop a mental illness.

Involvement of Similar Brain Regions

A mental illness and addiction often involve the same or similar brain regions. For example, psychoactive substances affect circuits in the brain that involve the neurotransmitter dopamine, and abnormal dopamine activity is also a factor in the development of mental illnesses such as schizophrenia and depression.


Certain environmental factors, such as a high stress level, a dysfunctional household or trauma can lead to substance abuse and the development of certain mental illnesses like anxiety, depression and post-traumatic stress disorder.

Six Common Mental Illnesses that Co-Occur with Addiction

Any mental illness can lead to self-medication with drugs or alcohol and increase the risk that someone will develop a substance use disorder. Likewise, drug abuse can lead to any number of mental conditions. Still, some mental illnesses co-occur with addiction more frequently than others.

Any mental illness can lead to self-medication with drugs or alcohol and increase the risk that someone will develop a substance use disorder.


Anxiety is the most common mental illness in the U.S., with around 40 million American suffering from one of a number of anxiety disorders.6 People with anxiety disorders often self-medicate their anxiety with drugs or alcohol, but doing so almost always makes the anxiety worse in the long run.

Mood Disorders

Mood disorders include bipolar and major depressive disorder, both of which often co-occur with substance use disorders. Around 20 percent of Americans with a mood disorder also have a substance use disorder.7

Bipolar disorder is characterized by alternating “mood episodes.” During a manic episode, an individual will have extremely high energy, and during a depressive episode, that same individual will sink into a deep depression.

A characteristic of manic episodes is the tendency to behave impulsively and engage in high-risk, pleasurable behaviors, which often leads to substance abuse. During depressive episodes, individuals may abuse substances to alleviate symptoms of depression or increase their energy levels. According to a study published in the journal Psychiatric Clinics of North America, up to half of all people with bipolar disorder also have a lifetime history of a substance use disorder.8

Major depressive disorder affects around 14.8 million American adults, or about 6.7 percent of the U.S. adult population.6 People with depression are likely to self-medicate with drugs or alcohol to relieve feelings of sadness or hopelessness, inevitably worsening the condition over time.

Major depressive disorder affects around 14.8 million American adults, or about 6.7 percent of the U.S. adult population.


Around 2.4 million American adults suffer from schizophrenia, a severe mental illness that affects how someone feels, thinks and behaves. Those who suffer from schizophrenia often lose touch with reality and experience hallucinations, delusions and problems with attention and memory. According to an article published in the American Journal of Drug and Alcohol Abuse, nearly half of those with schizophrenia have a lifetime history of a substance use disorder.9

People with schizophrenia commonly use nicotine and marijuana to alleviate some of the effects of this disorder. Nicotine helps to compensate for the cognitive deficits commonly seen with this disorder, and many patients use marijuana to cope with stress.

Since these and other drugs increase dopamine production, they may be used to combat the effects of antipsychotic medications, which interfere with dopamine activity and leave patients feeling joyless, according to an article published in the journal Schizophrenia Bulletin.10 In the vast majority of cases, illicit drugs worsen symptoms of schizophrenia over time.

Obsessive-Compulsive Disorder

According to an article published in the Journal of Anxiety Disorders, a study of a clinical sample of people with obsessive compulsive disorder, or OCD, found that 27 percent of the sample had a lifetime history of a substance use disorder.11 People with OCD may use opiates like percocet, alcohol or marijuana to relieve their symptoms, which include intrusive thoughts and compulsive, repetitive behaviors. Additionally, the very nature of OCD can lead to obsessive drug abuse that may in turn lead to an addiction.

Post-Traumatic Stress Disorder

Post-traumatic stress disorder, or PTSD, results from experiencing or witnessing a traumatic event, such as a natural disaster, accident or act of violence.

Symptoms of PTSD include:

  • Insomnia
  • Nightmares
  • Anxiety
  • Depression
  • Flashbacks

People with PTSD commonly self-medicate with alcohol to relieve these and other symptoms, because alcohol helps to compensate for reduced endorphin activity that often follows a traumatic experience. Alcohol can also help suppress memories and dreams.

According to an article published in the journal Alcohol Research & Health, PTSD is strongly associated with alcohol abuse.12 For example, a study of combat veterans with PTSD found that over half suffered from subsequent alcohol addiction, and a 1997 study found that 40 percent of people receiving inpatient treatment for a substance use disorder met the clinical criteria for a PTSD diagnosis.

Eating Disorders

Up to half of all people with an eating disorder abuse drugs or alcohol, compared with nine percent of the general population, according to an article in the journal Social Work Today.13 People with eating disorders may abuse stimulant drugs for weight loss and appetite control. They may use alcohol and other drugs to reduce the intensity of negative psychological symptoms resulting from the eating disorder.

Diagnosing Co-Occurring Disorders

Because many of the symptoms of addiction and mental illness overlap, it can be difficult to diagnose co-occurring disorders. To complicate matters, some withdrawal symptoms associated with various drugs of abuse mimic the symptoms of mental illness. In an addiction treatment setting, it’s often necessary to wait until the withdrawal symptoms have subsided and a period of abstinence has been observed before making a formal diagnosis.

Due to the high prevalence of co-occurring disorders, a universal and comprehensive approach has been developed to screen and assess for mental illness and substance use disorders in both psychiatric and addiction treatment settings. Those who seek psychiatric services are screened for a substance use disorder, and those who seek treatment for a substance use disorder are screened for mental illness.

Integrated Screening and Assessment

Screening for co-occurring disorders is usually part of the intake process in a psychiatric or treatment setting. The process is short and succinct. Patients answer a series of prescribed questions, which are then scored. The score determines whether sufficient evidence of a substance use disorder or mental illness is present. If it is, an in-depth assessment will be conducted.

During an integrated assessment, information is gathered to help a practitioner establish or rule out the presence of a co-occurring disorder. The integrated assessment is a 12-step process designed to evaluate a mental disorder in the context of the substance use disorder or vice versa.

During an integrated assessment, information is gathered to help a practitioner establish or rule out the presence of a co-occurring disorder.

The Substance Abuse and Mental Health Services Administration stresses the importance of the partnership between the individual being assessed and the assessing therapist.14 The assessment process is most successful when the patient is engaged in working to understand existing issues and develop treatment goals based on the formal diagnosis.

Integrated Treatment

A large body of research led to the practice of integrated treatment for co-occurring disorders in 1984. Prior to that, a patient was first treated for one disorder and then treated for the other. With integrated treatment came a higher level of success in treating both disorders, and the integrated model became the standard, best-practices method of treatment.

The integrated model of treatment ensures that each disorder is treated at the same time and in the context of the other disorder. Since having a substance use disorder increases the risk of mental illness and vice versa, integrated treatment dramatically improves the outcome for both the mental illness and the addiction.

Dual Diagnosis Treatment: Six Principles

The Substance Abuse and Mental Health Services Administration has developed six guiding principles for the treatment of co-occurring disorders:

  • Employ a recovery perspective to acknowledge that recovery from an addiction and mental illness is a process of change, and it occurs in stages. A successful dual diagnosis treatment plan will offer long-term continuity of care through an aftercare plan once treatment is complete.
  • Address multiple problems, such as medical issues, the need for housing or employment and dysfunction in the household. This is central to successful treatment and to overall good health and well-being.
  • Use a phased approach to treatment so that at each stage—engagement, stabilization, treatment and continuing care—the treatment addresses the recovery goals and meets the unique challenges of the stage.
  • Address real-life problems early to ensure that the co-occurring disorders are treated in the context of personal and social problems. By addressing issues like money management, social skills and skills related to an individual’s various roles in life, such as parent, student or employee, individuals are more likely to stay engaged in treatment and enjoy successful long-term recovery.
  • Address cognitive and functional impairments to ensure the individual being treated fully comprehends the implications of treatment and is able to adequately perform various tasks.
  • Institute an aftercare plan to ensure the individual has support at home and in the community once treatment is complete. The aftercare plan will include participation in a self-help group, ongoing therapy, continued monitoring of the mental illness and medications used to treat it and other supports that have been shown to help reduce the risk of relapse.

Dual Diagnosis Treatment Protocol

A wide range of therapies are employed in treating co-occurring disorders:15

  • Psychoeducational classes focus on helping individuals understand their mental illness and its relationship to and impact on the substance use disorder, and vice versa.
  • Pharmacotherapy is the practice of using medications to treat a mental illness or an addiction, or both. Medications are typically used during the detox phase of treatment to alleviate withdrawal symptoms, and they’re used to effectively treat the mental illness.
  • Behavioral therapies like cognitive-behavioral therapy help individuals learn to evaluate their thoughts, ideas, attitudes and behaviors and replace unhealthy ways of thinking and behaving with healthier ways.
  • Group therapy enables those in treatment to draw on the experiences and support of peers and work through their various issues with the help of others in similar situations.
  • Family therapy helps improve functioning within the family system to reduce stress and improve communication for better overall health and well-being of family members.
  • Alternative therapies like yoga, biofeedback and art therapy are designed to enrich treatment through a holistic approach that addresses issues of body, mind and spirit. Alternative therapies help reduce stress, and they offer a wide variety of ways to approach a problem for a better outcome. They also tend to lead to overall healthier lifestyle choices.
  • Specialized therapies for serious mental illnesses are employed as needed and include dialectical behavioral therapy to reduce self-harm behaviors and exposure therapy to help desensitize those with serious anxiety disorders.

Choosing a Dual Diagnosis Treatment Program

A treatment program that specializes in treating a dual diagnosis is absolutely essential for the successful treatment of co-occurring disorders. Some programs aren’t staffed, trained or otherwise equipped to offer integrated treatment, which is critical for successful recovery from a dual diagnosis.

A treatment program that specializes in treating a dual diagnosis is absolutely essential for the successful treatment of co-occurring disorders.

It’s important to choose a treatment program that either specifically includes integrated treatment in its programming or that specializes entirely in treating co-occurring disorders. Both types of programs focus on treatment as a collaboration among various treatment teams, and they have far better outcomes than programs that only address and treat an addiction.15

There is Hope

If you’re suffering from a mental illness and a substance use disorder, you may feel like there’s no hope for recovery due to the highly complex issues and interconnectedness between the disorders. But nothing could be farther from the truth. Integrated treatment works, and it vastly improves your physical and mental health and restores your sense of well-being.

Integrated treatment works, and it vastly improves your physical and mental health and restores your sense of well-being.

Taking the first step and entering treatment is often the most difficult part of recovery, but the sooner you acknowledge your need for help in sorting through the complicated issues surrounding your disorders and make the decision to enter treatment, the sooner you will see dramatic improvements in your overall quality of life.


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  3. Comorbidity: Addiction and Other Mental Illnesses. (2010, September). Retrieved from https://www.drugabuse.gov/sites/default/files/rrcomorbidity.pdf
  4. Dual Diagnosis. (n.d.). Retrieved from https://www.nami.org/Learn-More/Mental-Health-Conditions/Related-Conditions/Dual-Diagnosis
  5. Why Do Drug Use Disorders Often Co-Occur with Other Mental Illnesses? (2010, September). Retrieved from https://www.drugabuse.gov/publications/comorbidity-addiction-other-mental-illnesses/why-do-drug-use-disorders-often-co-occur-other-mental-illnesses
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  10. Volkow, N. D. (2009, May). Substance Use Disorders in Schizohrenia: Clinical Implications of Comorbidity. Schizophrenia Bulletin, 35(3), 469-472. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2669586/
  11. Mancebo, M. C., Grant, J. E., Pinto, A., Eisen, J. L., and Rasmussen, S. A. (2009, May). Substance Use Disorders in an Obsessive Compulsive Disorder Clinical Sample. Journal of Anxiety Disorders, 23(4), 429-435. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2705178/#R6
  12. Volpicelli, J., Balaraman, G., Hahn, J., Wallace, H., and Bux, D. (1999). The Role of Uncontrollable Trauma in the Development of PTSD and Alcohol Addiction. Alcohol Research & Health, 23(4), 256-262. Retrieved from http://pubs.niaaa.nih.gov/publications/arh23-4/256-262.pdf
  13. Ressler, A. (2008, July). Insatiable Hungers: Eating Disorders and Substance Abuse. Social Work Today, 8(4), 30. Retrieved from http://www.socialworktoday.com/archive/070708p30.shtml
  14. Co-Occurring Disorders Screening and Assessment: Integrated Screening. (2016, March 8). Retrieved from http://media.samhsa.gov/co-occurring/topics/screening-and-assessment/integrated-screening.aspx

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