Mental Health 101

Mental health: Definitions, diagnoses and use of language


Mental health is more than the absence of a mental illness. According to the World Health Organization (WHO, 2014):

Mental health is a state of well-being in which the individual realises his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to contribute to his or her community.

—World Health Organization


It’s important to understand that mental health and mental health problems are not opposing conditions. Someone with a diagnosed mental illness can experience good mental health, while someone without a diagnosed mental illness can experience difficulties at certain times of stress (e.g., job loss, housing changes, bereavement) (MHCC, 2009). Because the scope of mental health is so big, in this tutorial, we use the broader term “mental health problems” to refer to mental illness as well as poor mental health. This suggests that the two concepts are not conflicting, and that a diagnosis, or lack of diagnosis, does not define a person and their experiences.

Continuum model of mental health

Please click on the information button  to learn more.

So, what is a mental health problem or illness? Mental illnesses are conditions in which people’s thinking, mood and behaviours negatively impact their day-to-day functioning. Mental health problems can include depression, anxiety, schizophrenia and many others, as well as addictions (Public Health Agency of Canada, 2015a).

Mental illnesses can affect people of any age, but they often appear in teenage years or early adulthood. There are several types of mental illnesses. They can range from single, short-lived episodes to chronic disorders (Public Health Agency of Canada, 2015b).

Currently, there are no unbiased tests that diagnose mental illnesses. A diagnosis is based on a person’s subjective and personal symptoms, and the signs that physicians or relatives notice. For people working in the mental health field, having definitions of disorders is helpful when describing a mental health problem. The Diagnostic and Statistical Manual of Mental Disorders (5th edition; APA, 2013), also called the DSM-5, categorizes mental health disorders and offers examples of signs and symptoms of mental health problems.

Even though there are categories of diagnoses, everyone is different, even if they have the same diagnosis. It is most important to get to know a person, and to understand their experiences.

Note: There are differences in how clinicians diagnose their patients. They may be influenced by the culture and region in which they practice, or by the client’s race, class or gender. Additionally, what is identified as a disorder is always changing in response to new research or social awareness. The DSM categories are decided by committees that can be influenced by personal prejudices or by changes in public opinion. For example, homosexuality used to be a diagnosis requiring treatment. Research and public attitudes changed this.