The World Health Organization (WHO) defines mental health as being a state of wellbeing in which the individual realises his or her 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. According to this definition, being in good mental health does not solely mean not having an illness.

Mental illness is characterised by changes that affect a person’s thinking, mood and behaviour, and which cause distress or suffering. Mental illness is manifested through:

  • Signs of behavioural change, which people around the person affected can observe
  • Symptoms felt by the person affected

For instance, close relations may notice that the person affected isolates themselves. For their part, the person affected may have difficulty concentrating, or feel sad or anxious.

Health professionals and doctors take into account all signs and symptoms to evaluate the person’s condition and to render a diagnosis.

Most people in Québec will at one point or another be affected by mental illness, be it personally or through a parent, friend or colleague. Like physical illness, mental illness can strike anyone, regardless of age, sex, social status, education, nationality or ethnic origin.

About 20% of the Québec population, or 1 in 5 people, will experience a mental illness during their lifetime. Yet less than half of those who suffer from mental illness seek professional help. The WHO estimates that by 2020, depression will be the second leading cause of illness and disability after cardiovascular diseases.

The most known mental illnesses

The most known mental illnesses are the following:

There are other types of mental illnesses, including eating disorders.

Signs and symptoms

Signs and symptoms of mental illness may be more or less intense. The intensity varies according to the following:

  • The type of mental illness
  • The person’s personality
  • The person’s connections and relationships with their family and entourage
  • Social and economic factors (living environment, financial capacities, etc.)

Here are a few signs of behavioural change that people in the entourage of the person with a mental illness may observe:

  • Isolation
  • Drug and alcohol abuse
  • Stopping medication
  • Disorganization, meaning major difficulty in organising oneself and functioning normally. The person may experience a lack in judgement or harbour strange ideas
  • Memory loss
  • Difficulty taking care of family, professional and social obligations

Here are a few common symptoms someone with a mental illness may feel:

  • Loss of appetite
  • Insomnia
  • Nausea
  • Dizziness
  • Sadness
  • Euphoria (a feeling of great elation)
  • Difficulty concentrating

Signs and symptoms in children

The first signs of mental illness often occur during childhood. To learn how to recognise these signs in your child, read Recognising signs of mental illness in children.

When to consult

Do not wait until you are unable to perform your usual activities in order to consult resources and information for help. Do not hesitate in doing so, even if you are uncertain about the need. Unfortunately, many people wait until the situation is dire before seeking help. Here are some clues to help you see that you should consult:

  • Your symptoms have been for some time
  • Your anxiety attacks are repeated
  • You are experiencing distress
  • You feel that the solace given by your close relations is insufficient
  • You begin to have difficulty accomplishing your daily activities
  • People in your entourage see that you need help and tell you

Keep in mind that psychological suffering is often accompanied by physical symptoms. These symptoms will often reduce your ability to deal with day-to-day situations. Pay attention to these symptoms and do not hesitate seeking help. Read the Help and resources section to find resources available to you.


There are known treatments to cure or relieve symptoms of mental illness. Treatments allow people affected to regain control of their lives and daily activities. The earlier an affected person consults with a doctor, the better are her or his chances of recovery.

In most cases, mental illness is treated effectively through psychotherapy, medicine, or a combination of both.

Recommendations regarding medication

If your doctor prescribes you medication, it is important that you carefully follow the instructions for taking them.

Even if you feel better, continue the treatments as prescribed in order to avoid having the symptoms occurring again.

If you experience undesirable side effects due to medication, discuss the matter with your pharmacist or your doctor as soon as possible. If necessary, your medication can be adjusted or other medication may be recommended.


People with a mental illness sometimes develop problems with alcohol or drugs or addiction to these substances.

People who have both a mental illness and an addiction are more likely to:

  • Miss out on the positive effects of their treatments
  • Be hospitalised
  • Experience social hardships, such as homelessness, violence or trouble with the law
  • Have suicidal thoughts or behaviors

Protection and prevention

If you show symptoms of mental illness or if you simply wish to prevent the occurrence of mental illness, follow the following advice:

Find support

The support of a close relation, friend or colleague can make all the difference in preventing or getting over a mental illness. As such, do not hesitate to confide in someone if you are experiencing difficulties. Health professionals can also help and support you. Avoid isolating yourself if you have symptoms. See the Help and resources section to find resources available to you.

Adopt measures to maintain good mental health

Do not hesitate to change your habits by following advice for maintaining good mental health. These changes will help you eliminate factors that worsen or maintain your condition.

Overcome prejudices associated with mental illness

Sometimes people can hesitate to consult a health professional given their own prejudices, or that of others, towards mental illness. As such, some people do not consult either because they fear being judged by others, or because they believe it is impossible that they have a mental illness. Mental illnesses are not a personality weakness but conditions that can be cured.

Risk factors

The exact causes of every mental illness are unknown. Mental illnesses are the result of a combination of many factors that can trigger their development. These include:

  • Heredity, meaning if other family members have or have been affected by mental illnesses
  • Biological factors, which alter chemical balance in the brain (prolonged stress, substance consumption, etc.)
  • Characteristics of a person’s temperament, such as low self-esteem or difficulty adapting to different life situations
  • Illnesses or chronic physical health problems, such as cancer, illnesses affecting the thyroid gland, cardiovascular or respiratory diseases
  • The presence of stress factors in a person’s life, which may be related to:
    • Family environment (examples: death of a loved one, an abusive childhood, domestic violence, exposure to conflict)
    • Social environment (examples: homelessness, isolation)
    • Professional environment or financial situation (examples: job loss, low income)
  • Alcohol, drug or gambling addiction

People at risk

Certain people have a higher risk of having a mental illness. These include:

  • Children and adolescents that have experienced a difficult family environment or that are exposed to violence at school
  • People solely responsible for taking care of a family’s needs
  • People who have suffered sexual assault or domestic violence
  • Adults that do not work or who lose their job
  • People with a low income
  • Senior citizens that are alone or losing autonomy

Children that have or have had a mental illness are more at risk of having social problems or other health issues in adulthood.

Help and resources

Information and support resources

Resources are available for getting help or further information on mental health:

If you wish to be of help to a close relation with a mental illness, read the Living with a person suffering from a mental illness page to learn how to help them while respecting your own limits.

Resources for care and services

To receive care or services, or to find a psychotherapist with whom you feel comfortable, contact one of the following resources: