Concurrent Mental Illnesses and Substance Use Problems

What do we mean?

A concurrent mental illness and substance use problem means that someone experiences a mental illness and, at the same time, uses substances like alcohol or other drugs in ways that could cause harm.

Substance use is a problem when it negatively affects a person’s life or the lives of others.

Addiction or dependence (needing to use alcohol or other drugs to stop withdrawal) is one kind of substance use problem, but you don’t need to experience an addiction to experience harms to relationships, finances, or health from alcohol or other drug use.

It’s helpful to think of alcohol and drug use as a spectrum—if helpful use is at one end and harmful use is at the other end, there are varying levels of both in the middle.


What is the relationship?

People who experience a mental illness are more likely than others to also experience a substance use problem. Similarly, people who experience problems with alcohol or drug use are more likely to be diagnosed with a mental illness.

How strong is the connection? One major study that looked at people over their lifetime suggests that about half of people with one type of problem have the other type of problem, too.

There are three main ways that these concurrent problems interact. It’s important to keep in mind that each mental illness is different and alcohol and other drugs have different effects, so individual people will have unique experiences.

Substance use is a problem when it negatively affects a person’s life or the lives of others.
Mental illnesses can add to substance use problems

People who experience a mental illness might use substances like alcohol and other drugs in risky ways.

One theory is that alcohol or other drugs help people cope with different symptoms of mental illnesses. For example, people who experience some anxiety disorders might use a short-term anti-anxiety medication in ways that it wasn’t prescribed, which can increase the risk of dependence.

Some people may also use a substance to help manage the side effects of a psychiatric medication. Researchers think this may be one of the reasons behind the high rate of smoking in people diagnosed with schizophrenia, for example.

Substance use problems can add to mental illnesses

Alcohol and other drugs may add to the symptoms of mental illnesses. For example, psychosis is the group of symptoms that includes hallucinations (sensations that aren’t real) and delusions (beliefs that can’t be real).

It’s found in schizophrenia and other health problems. Several drugs can cause short-term symptoms of psychosis, and may lead to long-lasting symptoms in some people. For people who already experience psychosis, using alcohol and other drugs can make symptoms worse and harder to treat.

The same factors can increase the risk of both mental illnesses and substance use problems

Factors like genes or changes in the brain may make some people more likely to experience both a mental illness and a substance use problem.

External factors can also have an impact on mental health and substance use. Experiences of trauma, pain, poor housing, low income, loneliness, discrimination, poor access to services, easy access to substances, and other concerns that affect our community impact every individual’s health and well-being. These factors increase the risk of both mental illnesses and substance use problems.

What can I do about it?

If you’re concerned about a concurrent mental illness and substance use problem, it’s important to ask for help. Some people are concerned that talking about using illegal drugs might have negative consequences. In most cases, anything you tell your healthcare provider is private. Using illegal drugs won’t stop you from being able to receive help.

A real problem in Canada is that mental health and substance use systems are often separate. This means that many people have to receive treatment and support for their illnesses separately, or they are denied access to care for one problem because of the other problems they have. Fortunately, more service providers are now developing more integrated treatment options for concurrent problems.

It’s important to note that the goal of treatment for substance use problems may not be stopping all substance use. A more realistic goal for some people might be using substances in less risky or harmful ways (also known as harm reduction). Here are some options for treating concurrent problems:

The goal of treatment for substance use problems may not be stopping all substance use.

Psychotherapy or counselling is a common approach for both mental illnesses and substance use problems. There are many different types of psychotherapies, depending on the problems you’d like to address and your goals in treatment.

Many psychotherapy and counselling approaches work on building skills so you can cope with problems or challenges in healthier ways.


Medications may be used to treat mental illnesses, and they may be helpful in the treatment of some substance use problems. The type of medication depends on the illness or symptoms.

Some medications interact with alcohol and other drugs, so it’s a good idea to talk to your doctor or pharmacist if you have any concerns.

Social services and supports

People who experience concurrent disorders may face extra challenges in finding a healthy home, earning enough to live well, and other important aspects of living with dignity.

Extra supports can help people succeed in treatment, achieve their goals, and find a supportive community.

Do you need more help?

Many people start by talking with a doctor or other health care provider. These professionals can help you find more specialized services, if needed.

You can also contact a community organization like the Canadian Mental Health Association to learn more about support and resources in your area.

Founded in 1918, the Canadian Mental Health Association (CMHA) is the most established, most extensive community mental health organization in Canada. Through a presence in hundreds of neighbourhoods across every province, CMHA provides advocacy and resources that help to prevent mental health problems and illnesses, support recovery and resilience, and enable all Canadians to flourish and thrive.

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