Depression

Depression is a mood disorder, not simply a low patch. It brings low mood, or a loss of interest in things that used to matter, that stays for weeks at a time, and it changes sleep, appetite, energy and concentration along with it. Often the hardest part is that the things which normally help, work, company, being outside, are the first things that get difficult.

What depression is, and what it is not

Depression is not the same as sadness. The Centre for Addiction and Mental Health describes it as much more than unhappiness. The pattern a clinician looks for is low mood or loss of interest present most of the day, most days, for two weeks or longer, together with changes in sleep, appetite, energy or concentration, and enough interference with daily life that work, school, relationships or looking after yourself are affected.

It is also not a character flaw or a failure of effort. Depression involves genetic, biological, environmental and psychological factors together, and it often sits alongside another illness: a thyroid problem, diabetes, heart disease or long-term pain all raise the risk. Some people have one episode in a lifetime and others have several. In Canada, 14.0% of people aged 15 and older have had a major depressive episode at some point in their lives.

Signs and symptoms

• Low mood, emptiness or irritability most of the day, most days, for two weeks or longer
• Losing interest or pleasure in things you normally enjoy, including people
• Changes in sleep: trouble falling asleep, waking early, or sleeping far more than usual
• Changes in appetite, and eating much more or much less than you used to
• Feeling tired and slowed down, or feeling restless and unable to settle
• Trouble concentrating, remembering things or making even small decisions
• Feelings of worthlessness or guilt that are out of proportion to what is happening

No two people get the same set. Some sleep constantly and others barely sleep; some feel flattened and slowed while others feel agitated. Symptoms also shift over the course of an episode, which is part of why clinicians in Canada use the same short questionnaire at repeat visits rather than relying on one conversation.

What raises the risk

Some risk factors cannot be changed:

• A family history of depression or bipolar disorder
• Being female, since depression is about 1.5 times more common among women than men worldwide
• Past trauma, including childhood adversity, which the Centre for Addiction and Mental Health describes as a significant contributor
• Another long-term illness such as diabetes, heart disease, chronic pain or a thyroid problem

Others can often be worked on, usually with support from a health care team:

• Alcohol and other substance use
• Broken or short sleep, long periods of inactivity, and stretches of social isolation
• Some prescription medicines, which a prescriber can review with you

How depression is diagnosed in Canada

Depression is most often identified by a family doctor or nurse practitioner. They ask about mood, interest, sleep, appetite, energy and concentration, how long the symptoms have lasted, and how much they are affecting work, school, relationships and daily tasks. Short validated questionnaires such as the PHQ-2 and PHQ-9 are commonly used, both to screen and to track change over time, an approach the Canadian Network for Mood and Anxiety Treatments calls measurement-based care. Blood tests are ordered only when a physical cause is suspected, such as a thyroid problem, and brain scans and EEG are not part of a routine assessment. A clinician will also ask about alcohol and drug use, medicines, and any past periods of unusually high mood or energy, because that changes the diagnosis. Some people are referred on to a psychiatrist, psychologist, social worker or a community mental health programme.

Treatment and day-to-day management

Clinical research for Depression is enrolling. See the current studies ↓

Canada has national guidelines for depression, published by the Canadian Network for Mood and Anxiety Treatments and last updated in 2023. They set out several kinds of first-line care rather than one route. Depending on how severe an episode is, what has helped before, and what is available where you live, a health care team may discuss:

• Psychoeducation and daily-life measures, including sleep routines and structured physical activity, and light therapy for depression that follows a winter pattern
• Psychological treatments, most often cognitive behavioural therapy, behavioural activation and interpersonal therapy, delivered in person, in a group, or through a guided digital programme
• Antidepressant medicines, of which the guidelines list several as first-line options, with close follow-up in the first weeks to review response and side effects
• Measurement-based care, meaning repeat use of a rating scale such as the PHQ-9 so that you and your clinician can see what is changing
• Neurostimulation, including repetitive transcranial magnetic stimulation and electroconvulsive therapy, used in severe episodes and where other approaches have not worked

Which of these fits depends on the person, and access differs a great deal across the country. These are decisions for you and your own clinician, and this page is not a recommendation about any of them.

When to talk to a doctor

• If you are thinking about suicide or about hurting yourself, help is available now. The 9-8-8 Suicide Crisis Helpline answers calls and texts from anywhere in Canada, free, 24 hours a day, every day of the year: call or text 9-8-8. If you are in immediate danger, call 911 or go to your nearest emergency department.
• Book an appointment with your family doctor or nurse practitioner if low mood, loss of interest, or changes in sleep, appetite or concentration have lasted two weeks or more, or are affecting your work, school, relationships or your ability to look after yourself or someone else.
• Contact your prescriber or health care provider promptly if you feel worse after starting or changing a medicine, if you are drinking or using substances more in order to cope, if you are not eating or drinking, or if you are hearing or seeing things other people do not.

Why clinical research matters for depression

Depression is common and Canada has established care pathways for it, but not everyone gets better with the first thing they try, and there is no test that tells a clinician in advance which treatment will suit a particular person. The 2023 Canadian guidelines added a framework for difficult-to-treat depression, in which the focus shifts from clearing every symptom towards the best possible functioning and quality of life, and they note that only about 20% of people with major depressive disorder worldwide receive adequate treatment. In Canada the gap shows up in a specific place: Statistics Canada found counselling to be the least met need, unmet or only partly met for 30.5% of people with a mood, anxiety or substance use disorder, against 7.0% for medication. Studies are currently looking at markers that could match people to treatments sooner, rapid-acting medicines, newer neurostimulation methods, psychological therapies in digital and group formats, treatments aimed at winter-pattern and postpartum depression, and ways of organising care that shorten the wait for therapy.

Clinical studies are how any of that gets tested. Taking part is voluntary, you give informed consent before anything begins, and you can stop at any time without affecting the care you get from your own doctor. Joining a study does not mean giving up your current treatment, and no one can tell in advance whether a study will help you personally.

Learn more from Canadian sources

• 9-8-8 Suicide Crisis Helpline: call or text 9-8-8, any time
• Centre for Addiction and Mental Health: depression
• Mood Disorders Society of Canada: education and peer support
• Canadian Mental Health Association: find your local branch
• Statistics Canada: mental disorders and access to mental health care