Published on: Friday, March 19, 2021

The Treatment Advocacy Center’s Office of Research and Public Affairs published a new evidence brief today that sheds light on the numerous challenges faced by people with serious mental illness and co-occurring substance use disorders.

A dual diagnosis can have a multitude of consequences on an individual’s life: People with co-occurring disorders are more vulnerable to becoming involved with the criminal justice system or experiencing homelessness and it is much more difficult for them to access the necessary treatment that addresses both disorders. 

The 38-page evidence brief, Dual Diagnosis: Serious Mental Illness and Co-occurring Substance Use Disorders, offers an extensive analysis of over 150 sources of prominent existing research, including the Substance Abuse and Mental Health Services Administration’s Mental Health Surveillance Study, one of the most robust surveys of mental health facilities in the country.

Key findings include:

  • One in four people with serious mental illness also have a substance use disorder.
  • Only 12.7% of people with co-occurring serious mental illness and substance use disorders received any treatment for both conditions in 2019.  
  • People with serious mental illness are more likely to smoke tobacco and misuse alcohol compared to those without mental illness. 
  • Cannabis is one of the most common drugs used by people with serious mental illness. Almost 40% of individuals with serious mental illness used marijuana in 2019.
  • Individuals with co-occurring substance use disorder and serious mental illness are overrepresented in every part of the criminal justice system and are more likely to experience homelessness.