Mental Health, Substance Use, and Co-Occurring Disorders

You will learn about mental health conditions, substance use disorders, and supporting individuals with co-occurring disorders. Upon completion, you should be able to:

  • Discuss the continuum of mental and emotional health
  • Define co-occurring disorders
  • Explain why co-occurring disorders are common among those with mental health concerns or substance use disorders

The Continuum of Mental and Emotional Health

The World Health Organization defines mental health as:

“a state of well-being in which the individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community (2018).”

Mental health conditions affect the way a person thinks, feels, reacts, and behaves.  Sometimes they affect people’s moods, beliefs, perceptions, and impulses in different ways.  But some of the ‘symptoms’ we associate with mental health disorders are things that almost everyone experiences to some degree at some point, often making it difficult to decide this behavior is “normal” and what behavior is not. 

It may be helpful to think of mental and emotional health on a continuum.  For example, some people live with low grade depression, but may go through periods where their depression is so deep they cannot function, while others may cycle in and out of unpredictable highs and intolerable lows. People with anxiety problems often find ways of coping when anxiety levels are high, but sometimes panic sets in or fear keeps them from leaving the house and interferes with their daily routine. When an individual cannot keep their perceptions about the world or impulsive behaviors from causing discomfort or harm to themselves or others, they may have an untreated mental health disorder.

The Intersection of Mental Health and Substance Use

Co-occurring disorders (CODs) generally refers to people with both mental health and substance use disorders. According to current research, CODs are relatively rare, affecting less than 3% of the U.S. population. However, about half of those who experience one disorder will also experience the other at some point in their lifetime.

There are a lot of different theories about the reasons that so many people with one condition also experience the other, but what we can say for certain is that both types of conditions share a lot of common risk factors.  These risk factors are often complex and may be interrelated.  For example:


Traumatic events, by definition, cause people deep distress.  When that distress persists or when people re­experience the emotional upheaval caused by traumatic events, sometimes they find drugs/alcohol provides relief.  For some people that relief is a powerful reinforcer that becomes a pathway to addiction. A history of trauma is associated with trauma-related mental health conditions, addictive disorders, and a variety of other mental health conditions.

Adverse Childhood Experiences

The cumulative effects of growing up with experiences such as having an incarcerated parent, living with discrimination, any form of child abuse, and other difficult or traumatic conditions can contribute to the development of addictive disorders and both mental and physical health problems.  Research shows that the more of these different types of experiences dominate an individual’s childhood, the more likely they are to develop serious mental health and addictive disorders. 


Not so long ago, scientists thought they would someday discover a gene for drug addiction, one for alcoholism, and so on.  Today we have a broader understanding of genetics, although there are still plenty of unknowns.  Most scientist understand that a complex interplay of multiple genetic factors interact with environmental influences including gender and culture.  Some aspects of mental health and addictive disorders may have genetic components, but the same can be said of allergies, responses to medications, and certain types of cancer.

Examples of some of the more common mental health disorders that co-occur with addictive disorders include:

  • Trauma-related disorders
  • Mood disorders
  • Anxiety disorders
  • Psychotic disorders 
  • Eating disorders 

You can learn more about the different types of mental health disorders at the National Alliance on Mental Illness:

The Role of Peer Support Specialists

Peer support specialists help recovering individuals focus on strengths, increase resilience factors, and turn survival skills developed out of necessity into life skills that lead to opportunities.  The frequency of co-occurring disorders makes it essential for peer support specialists to understand both mental health and substance use disorders and to be able to promote co-occurring recovery.

Many people with mental health and addictive disorders have had a hard time finding the kind of holistic care they needed.  Every individual has different recovery goals, priorities, and challenges.  Moreover, these priorities are likely to change over time.  Peer support specialists help people clarify and achieve their recovery goals and improve their quality of life.  Although mental health and addiction recovery share many common elements, people in co-occurring recovery may need specific types of support at different points along the way. 

Peer support specialists spend time with people, get to know them, and are familiar with their habits and demeanor.  As a peer, you may be able to notice sudden or extreme changes before anyone else does. Meeting with your supervisor to discuss your observations can play an important role in keeping people healthy.

Remember, most conditions affect the mind AND body and many individuals with mental health and addictive disorders are dealing with both physical and emotional pain.  Peer support specialists can promote health, prevent harm, and encourage self-care including regular visits to a primary care provider to make sure medical issues aren’t contributing or causing unnecessary problems.

The Mental Health Commission of Canada has an online self-check tool that breaks down different elements of the continuum of mental health. – View here


National Institute on Drug Abuse (2018.). National Institutes of Health; U.S. Department of Health and Human Services. Comorbidity: Substance Use and Other Mental Disorders.

Han, B., Compton, W. M., Blanco, C., & Colpe, L. J. (2017). Prevalence, Treatment, And Unmet Treatment Needs Of US Adults With Mental Health And Substance Use Disorders. Health Aff Proj Hope. 2017;36(10):1739-1747. doi:10.1377/hlthaff.2017.0584

Treating Substance Use Disorder in Older Adults: UPDATED 2020 [Internet]. Treatment Improvement Protocol (TIP) Series, No. 26. Rockville (MD): Substance Abuse and Mental Health Services Administration (US); 2020.

World Health Organization. (2018, March 30). Mental health: strengthening our response.