Co-morbid Psychiatric and Substance Use Disorders: Challenges in Diagnosis and Treatment

By Lauren DeSouza- Master of Public Health, Simon Fraser Public Research University – Canada
Staff Research and Content Writer

This article is reproduced herein with permission of the copyright holder.

© Copyright – SUD RECOVERY CENTERS – A Division of Genesis Behavioral Services, Inc.,
Milwaukee, Wisconsin – December 2021 – All rights reserved.

Co-morbidity Defined

A “co-morbidity” refers to when a person is diagnosed with both a substance use disorder and a psychiatric disorder. Co-morbidities are also referred to as a “dual diagnosis” or “co-occurring disorders”. 

Substance use disorders can include alcohol use disorder, opioid use disorder, cannabis use disorder, tobacco use disorder, and  cocaine use disorder, while psychiatric disorders can include major depressive disorder, bipolar disorder, anxiety disorder, and schizophrenia. 

Over 50% of people with substance use disorders will also experience a mental illness at some point over the course of their lives. Some commonly occurring co-morbidities are:

  • Alcohol use disorder and major depressive disorder
  • Addictions and eating disorders in women particularly
  • Cannabis use disorder and psychotic or bipolar disorders

Unfortunately, psychiatric disorders often go unrecognized and untreated in those with substance use disorders, as effects of substance use can be similar to those of some psychiatric disorders. Without treatment for their psychiatric disorder, people have less success with treatment for their substance use disorder, are more at risk of relapse, and are at a higher risk of suicide.

Screening for Co-morbidities

It is often difficult for health care providers to detect psychiatric conditions, since the symptoms can be similar to those of substance use. Health care providers will try to separate the symptoms of psychiatric disorders from the effects of substance use, by looking at the timing of symptoms and the severity of symptoms. They will look at if the symptoms started before the person started using substances, and if the symptoms go away when the person stops using substances. If someone has a family history of a certain psychiatric disorder, this can also help the health care provider detect the disorder in their patient.

Treating Co-morbidities Together

It is important for health care providers to screen all patients for psychiatric conditions when they are in treatment for substance use disorders. Systematic screening for all patients can help prevent disorders from going unnoticed and untreated. Early screening and detection of psychiatric disorders allows for patients to start treatment earlier and to be referred to specialists if necessary, which can help improve their treatment outcomes. As well, treating both substance use and psychiatric disorders at the same time can lead to better outcomes for patients.


Crockford, David. 2021. Current Challenges with Comorbid Psychiatric and Substance Use Disorders. The Canadian Journal of Addiction: 12 (3):4-6. 

doi: 10.1097/CXA.0000000000000121