In Canada, the term concurrent disorder is most commonly used to describe the co-occurrence of mental illness and substance use. However, terminology can vary. For example, in the United States, the term “dual diagnosis” is used interchangeably with “concurrent disorder” whereas in Canada, “dual diagnosis” typically refers to someone who has both a developmental disability and a mental health condition. Another commonly used term, comorbidity, refers to the presence of two or more health conditions in an individual, regardless of the types involved. In Canada, when we are discussing the co-occurrence of mental illness and substance abuse we use the term concurrent disorder.
Many people living with mental illness also struggle with substance use, and vice versa. Often mental illness and substance abuse influence each other in powerful ways — hence the term concurrent disorder.
How Common Are Concurrent Disorders in Canada?
Despite growing awareness, concurrent disorders are still underreported and often misunderstood. According to the Canadian Centre on Substance Abuse, “more than 50% of those seeking help for an addiction also have a mental illness, and 15 to 20% of those seeking help from mental health services are also living with an addiction.” For individuals living with a more severe mental illness, the likelihood of developing a substance use issue during their lifetime increases significantly, with estimates ranging from 40% to 60%.
Newer research suggests that concurrent disorders may be even more widespread than previously thought. While a single year’s data offers a snapshot, long-term studies reveal patterns of co-occurrence that highlight just how intertwined these conditions can be. Furthermore, because mental health and addictions services can be independent of one another, getting help for both conditions can be a challenge.
Why Do Mental Illness and Substance Use Often Co-Occur?
There are several reasons why mental health challenges and substance use so often appear together. One explanation is that substance use can intensify existing mental health symptoms or even trigger the onset of a mental illness in individuals who may already be vulnerable.
There are also shared risk factors that increase the likelihood of both conditions emerging. Genetics can play a role, as can life experiences. Exposure to childhood trauma, neglect, chronic stress, or unstable living conditions may all contribute to the development of both mental illness and substance use disorders.
Many individuals also turn to substances as a form of self-medication. Using alcohol, cannabis, or other drugs may offer temporary relief from feelings of anxiety, depression, or emotional pain — but over time, this coping strategy can lead to dependency and further emotional distress. The cycle is difficult to break without targeted, compassionate support.
Treating Concurrent Disorders
No single treatment fits all, but evidence-based therapies can help people manage both mental illness and substance use. Among the most commonly used is Cognitive Behavioural Therapy (CBT), which focuses on identifying and changing harmful thought patterns and behaviours. Therapists can adapt CBT to treat both addiction and mental health issues using a structured, practical approach.
Another promising approach is Motivational Interviewing, a client-centred technique that helps individuals explore and resolve their ambivalence toward change. Clinicians often use it in early treatment stages to support a person’s readiness for recovery.
That said, there are significant challenges in diagnosing and treating concurrent disorders. Traditional treatment models often separate mental health and substance use services. This approach can result in fragmented care that doesn’t fully address either issue. The symptoms of one condition can often mask those of the other. For instance, depression might be mistaken for substance withdrawal, or anxiety might be misread as a side effect of drug use. As a result, the underlying issues may remain untreated.
An integrated treatment approach, where both conditions are addressed together in a coordinated plan, is considered the gold standard. Unfortunately, this level of care is not consistently available across Canada.
Recovery and Support
Living with a concurrent disorder can feel isolating, but recovery is entirely possible. As with any journey toward wellness, it requires time, patience, and a team of differentiated supports. Integrated care, when available, leads to better outcomes and reduces the risk of relapse or rehospitalization. According to the Mental Health Commission of Canada, a personalized approach that combines therapy, medical, and social connection supports are key to long-term recovery.
Support systems play a vital role. Family members and friends often serve as crucial anchors during the recovery process, offering encouragement and accountability. Peer support networks connect individuals with others who have lived experience, offering a powerful reminder that no one has to navigate their struggles alone. Community-based programs (e.g. traditional 12-Step programs, and Rapid Access Addiction Medicine (RAAM) Clinics) can also provide access to resources, counselling, and harm reduction tools tailored to people with concurrent disorders.
In Ontario, several organizations provide specific support. The CAMH Compass Program offers consultation and coordination services for youth with complex mental health needs, including concurrent disorders. Ontario Shores offers a dedicated Concurrent Disorders Service focused on adults with both mental illness and substance use concerns. Similarly, the Canadian Mental Health Association provides integrated support through their Concurrent Disorders Program.
Concurrent disorders are common, complicated, and deeply personal. Biological, psychological, and social factors shape each person’s experience in different ways. But while the path forward may not be easy, recovery is possible with the right tools and support.
Eli’s Place Communications Team
Our Eli’s Place blogs are developed & written by the Eli’s Place Editorial Team — a collaboration between staff and volunteers committed to raising awareness about serious mental illness in Canada. We aim to inform, inspire, and engage with readers who care about mental health and recovery.
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