Mental health and mental illness: what’s the difference?
Mental health and mental illness are often used interchangeably, but they are not the same thing.
“Mental health” is a concept similar to “physical health”: it refers to a state of well-being. Mental health includes our emotions, feelings of connection to others, our thoughts and feelings, and being able to manage life’s highs and lows.
The presence or absence of a mental illness is not a predictor of mental health; someone without a mental illness could have poor mental health, just as a person with a mental illness could have excellent mental health.
Problematic substance use is sometimes linked to poor mental health or mental illness; it can be a coping strategy for untreated trauma, pain, challenging thoughts or emotions, or other health symptoms.
Who is affected?
Everyone has mental health and will experience challenges regarding their mental well-being, but not everyone will experience a mental illness.
Mental illness indirectly affects all Canadians at some time either through their own experience, or that of a family member, friend or colleague.
In any given year, 1 in 5 people in Canada will personally experience a mental health problem or illness.
By age 40, about 50% of the population will have or have had a mental illness.
Mental illness affects people of all ages, education, income levels, and cultures; however, systemic inequalities such as racism, poverty, homelessness, discrimination, colonial and gender-based violence, among others, can worsen mental health and symptoms of mental illness, especially if mental health supports are difficult to access.
Major depression affects approximately 5.4% of the Canadian population, and anxiety disorders affect 4.6% of the population.
About 1% of Canadians will experience bipolar disorder (formerly called “manic depression”), and another 1% will experience schizophrenia.
Eating disorders affect approximately 1 million Canadians – between 0.3-1% of the population. They impact women at a rate ten times that of men, and have the highest rate of mortality of any mental illness.
Substance use disorders affect approximately 6% of Canadians.
In Canada, suicide disproportionately impacts Indigenous peoples; the rate of suicide among First Nations is three times higher than among non-Indigenous Canadians, and nine times higher among Inuit.
The mortality rate due to suicide among men is three times the rate among women, but girls and young women are three times more likely than men to harm themselves and be hospitalized from self-harm.
How does mental illness impact youth?
When it comes to mental illness, youth is a critical period: most people living with a mental illness see their symptoms begin before age 18.
Approximately 20% of Canadian youth are affected by a mental illness or disorder
In 2011, 11% of 15-24 year olds reported experiencing depression .
Between 2008–2009 and 2018–2019, among youth there was a 61% increase in emergency department visits and a 60% increase in hospitalizations for mental disorders. 
Suicide is the second leading cause of death among youth and young adults between 15-34 years.
In Canada, only 1 out of 5 children receive appropriate mental health services.
What causes mental illness and substance use problems?
Mental illnesses are caused by a complex interplay of genetic, biological, personality and environmental factors.
Life events such as violence and trauma during childhood or adulthood can give rise to mental health and substance use problems if supports for recovery are not available or sought.
Environmental factors play an important role in our mental health: access to safe and affordable housing, meaningful education and employment, leisure activities, the support of a community, access to land and nature, freedom from violence, and good access to health care and mental health services all support good mental health.
Stigma and discrimination attached to mental illnesses and substance use problems present a serious barrier not only to diagnosis and treatment but also to access to employment, housing, and other basic necessities. Stigma both creates and deepens social marginalization.
The symptoms of mental illnesses can be treated and very often managed effectively; with the right supports, people with mental illnesses can thrive.
What are the costs related to mental illness?
Without the right supports, people with mental illness and substance use problems, their caregivers and their families can experience great suffering; we need a robust mental health care system with a wide range of programs and services, including health promotion and wrap-around supports like housing and employment services, to ensure that people receive the preventative care, treatment and the supports they need to recover and thrive.
There is also an economic cost when mental illness and substance use problems go untreated and when we fail to invest in promotion, prevention, and other support services.
The economic cost of mental illnesses to the Canadian healthcare and social support system was projected as $79.9 billion for the year 2021. 
Because public mental health services are underfunded and have long wait times, many people rely on their employer-based benefits or bear the personal cost of private services. Canadians spend an estimated $950 million a year on psychologists in private practice. About 30% of this is paid out-of-pocket while the remainder is paid through employment-based private health insurance plans.