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Detailed Overview: 30-Minute Read

Major Depressive Disorder

This broad overview about major depressive disorder covers the signs and symptoms, diagnosis, and treatments.



Basic facts about depression and major depressive disorder.

What is major depressive disorder?

Major depressive disorder is a serious medical illness. It’s more than just a feeling of being sad or “blue” for a few days. The symptoms persist and interfere with your everyday life. It can cause severe symptoms that affect how you feel, think, behave, and handle daily activities, such as sleeping, eating, or working.

It is an illness that can affect anyone—regardless of age, race, income, culture, or education. It is more common in women and often begins in teens and young adults.

There are effective treatments for depression, including psychotherapy (talk therapy), antidepressants, and others. If left untreated, though, depression may continue for weeks, months, or longer; and may lead to significant disability or death.

While the term “depression” or “depressed” is sometimes used as a general term for feeling sad, health care professionals are generally referring to a more severe and persistent form of depression, known as “major depression” or “major depressive disorder”, also sometimes referred to as “clinical depression”.

Depression in older adults is sometimes referred to by health professionals in different ways, such as “late life depression” or “late onset depression” or, more generally, “geriatric depression”. This is because some older adults may have a new diagnosis in older adulthood (over age 65); while others may have had depression at an earlier point in their life and there is now a recurrence.

How common is depression in older adults? 

According to the World Health Organization, major depression occurs in 7% of the general older population. This is probably a reasonable estimate of major depression in Canadian older adults, though it may be an underestimate. In a 2017 survey, 38% of Canadians said they had experienced persistent sadness and hopelessness for more than a couple of weeks; and in a 2016 survey, 40% said they had experienced feelings of anxiety or depression, but never sought health care for it.

Many older adults experience depressive symptoms that do not meet the full criteria for depression (see below under Symptoms).

Depression may be less well recognized in older adults, whether because some signs and symptoms are thought to be signs of normal aging; or because some older adults may not discuss how they are feeling with health care providers.

What are the causes of depression? 

While the exact cause of major depressive disorder is not known, there are a variety of factors that may play a role, including genetic, biological, environmental, and psychological factors. As part of the assessment of depression, it is very important to rule out medical causes of depression.

Medical conditions that can cause depression

  • Chronic pain that doesn’t go away with treatment 
  • Abnormal levels of calcium, sodium, or potassium in the blood 
  • Not enough vitamin B12 or folate in your diet or vitamin deficiency from other causes
  • Anemia (your blood produces a lower-than-normal amount of healthy red blood cells)
  • Too much or too little thyroid hormone 
  • Too much or too little adrenal hormone 
  • Dementia
  • Stroke
  • Side effects caused by certain medicines 
  • Alcohol or other substance use disorders

Factors associated with depression in older adults

In older adults, life changes can increase the risk for depression or make existing depression worse. Some of these changes include:

  • A move from home, such as to a retirement or long-term care home
  • Retirement
  • Chronic illness or pain
  • Children moving away
  • Spouse or close friends passing away
  • Loss of hearing or vision
  • Loss of independence (for example, problems getting around or caring for oneself, or loss of driving privileges)

Sometimes depression may develop with no apparent cause or reason.

Who is at risk for depression?

  • Genetic factors: Depression is known to run in families, suggesting that genetic factors contribute to the risk of developing this disease. However, research into the genetics of depression is in its early stages, and very little is known for certain about the genetic basis of the disease. 
  • Environmental factors: The disorder can be triggered by substance abuse, certain medications, or stressful life events (such as divorce or the death of a loved one). Other risk factors include difficulties in relationships or social isolation, unemployment, financial problems, and childhood abuse or neglect.
  • Physical/medical illnesses: As noted above, some physical illnesses, such as cancer, thyroid disease, and chronic pain, are also associated with an increased risk of developing depression. Poor levels of nutrition/malnourishment can lead to depression whether as a direct effect or through vitamin deficiencies.
  • Brain structure and function: While this is still an active area of research, people with evidence of damage to the brain in the frontal lobes and areas of the ‘white matter’ that helps to insulate and connect brain neurons may be at increased risk of depression. Damage to blood vessels in the brain (“vascular lesions”) has also been associated with late onset depression.

It is likely that these factors interact to determine the overall risk of developing this disease.



Signs and symptoms, depressive episodes, and the different types of depressive disorders.

What are the symptoms of depression? 

A major depressive episode is defined as experiencing five or more of the symptoms below (one of which must be either depressed mood or loss of interest/pleasure in everyday activities) most days and most of the day for at least two weeks. These are a change from normal, are severe enough to interfere with a person’s day-to-day function, and are not better explained by a different disorder or condition.

  • Persistent sad, anxious, or “empty” mood
  • Feelings of hopelessness or pessimism
  • Feelings of irritability, frustration‚ or restlessness
  • Feelings of guilt, worthlessness, or helplessness
  • Loss of interest or pleasure in hobbies or activities
  • Decreased energy, fatigue, or being “slowed down”
  • Difficulty concentrating, remembering, or making decisions
  • Difficulty sleeping, early morning awakening, or oversleeping
  • Changes in appetite or unplanned weight changes
  • Aches or pains, headaches, cramps, or digestive problems without a clear physical cause and that do not ease even with treatment
  • Suicide attempts or thoughts of death or suicide

However, depression in older adults may be hard to detect. Common symptoms such as fatigue, appetite loss, and trouble sleeping can be part of the aging process or a physical illness. As a result, symptoms of early depression may be ignored, or confused with other conditions that are common in older adults.

What are the types of depression?

Two common forms of depression are: 

  1. Major depressive disorder which includes symptoms of depression most of the time for at least 2 weeks that typically interfere with one’s ability to work, sleep, study, and eat.
  2. Persistent depressive disorder (also known as dysthymia) – a more chronic form of depression with very similar symptoms, but that typically lasts much longer, and at least 2 years. 

Major depressive disorder often presents with distinct ‘episodes’ that are very different from the person’s normal mood and function; whereas persistent depressive disorder is much more chronic/longstanding, and people have typically felt a low-level of depression for many years. It’s also possible to have both disorders; and people with persistent depressive disorder are at increased risk of developing major depressive disorder as well (“double depression”).

Other forms of depression that are sometimes referred to:

  • Seasonal affective disorder: which comes and goes with the seasons, typically starting in late fall and early winter (in North America) and going away during spring and summer. Light therapy may be a helpful treatment in this sub-type of depression.
  • Depression with symptoms of psychosis: a severe form of depression where a person experiences symptoms of psychosis, such as delusions (disturbing, false fixed beliefs) or hallucinations (hearing or seeing things that others do not see or hear). Often the delusions or hallucinations are very ‘negative’ or disturbing for the person; for example, feeling that their body is rotting from the inside, or that they can hear voices saying negative, critical comments about them.
  • Bipolar depression: People with bipolar disorder (previously known as manic-depressive illness) may frequently experience depressive episodes, but a person with bipolar disorder also experiences manic or hypomanic episodes; these are unusually elevated moods in which the individual might feel very happy, irritable, or “up,” with a marked increase in activity level. 

Your health care provider may ask you questions to assess for a seasonal pattern, symptoms of psychosis, or a history consistent with bipolar disorder.

What else could it be if not depression? 

Common symptoms such as fatigue, appetite loss, and trouble sleeping can be part of the aging process or a physical illness. 

Depression, especially in midlife or older adults, can co-occur with other serious medical illnesses, such as diabetes, cancer, heart disease, Parkinson’s disease, dementia, and others. These conditions are often worse when depression is present, and research suggests that people who have depression and another medical illness tend to have more severe symptoms of both illnesses.

Sometimes medications taken for these physical illnesses may cause side effects that contribute to depression.

Some symptoms of depression may occur when someone has delirium, a mental state in which a person is confused and has a change in the awareness of their surroundings. Delirium often occurs in hospital when an older adult has a serious illness, and may be associated with anxiety or depressive symptoms.

An adjustment disorder is an emotional or behavioural response to a stressful event or change in a person’s life circumstances. The person experiences more stress than would normally be expected, and the reaction causes significant problems in function. This might occur after losing your job, the loss of an important relationship, or as a response to a serious medical issue. Typically, when the stressor goes away, the person’s mood returns to normal. (Or the person adapts and copes with the stressor, and their mood bounces back.) While depressed mood may be a symptom of adjustment disorder, it tends to be less severe and persistent than major depressive disorder, with fewer other symptoms.

Substance use disorders like alcohol or opioid use disorders may be associated with signs and symptoms very similar to depression. It’s also possible to people to have both a substance use disorder and depression at the same time.

What other mental health conditions may co-occur with depression?

There are a wide range of other mental disorders that may co-occur with major depression, including substance use disorders and anxiety disorders like panic disorder and generalized anxiety disorder. It’s important for your doctor to ask about these other disorders, as you may need treatment for more than one condition at the same time. To learn more about anxiety disorders, you can view that topic here.



Assessment and diagnosis.

How is depression assessed and diagnosed?

If you think you may have depression, you should talk to your doctor or nurse practitioner about depression screening, treatment options and/or a referral to a mental health professional. A proper assessment will review what has been happening with your mood, life circumstances, how you are managing day-to-day, and ask about other signs and symptoms you might be having. In addition, your health care provider will ask questions about your physical health, medications, substance use, and your medical history. 

Depression Screening

A depression screening is used to help diagnose depression, understand how severe depression may be, and help figure out what type of depression you have.


To be diagnosed with depression, an individual must have five depression symptoms every day, nearly all day, for at least 2 weeks. One of the symptoms must be a depressed mood or a loss of interest or pleasure in almost all activities

Older adults with depression commonly experience sadness or grief or may have other less obvious symptoms. They may report a lack of emotions rather than a depressed mood. Older adults are also more likely to have other medical conditions or pain that may cause or contribute to depression. In severe cases of depression, memory and thinking problems (called pseudo-dementia) may be prominent.

What can I expect in a depression screening?

During a depression screening, you’ll answer a standard set of questions. Your provider may ask the questions, or you may fill out a questionnaire to discuss with your provider later.

In general, the questions ask you about changes you’ve noticed in your:

  • Mood
  • Sleep habits
  • Appetite or weight
  • Energy levels
  • Ability to focus your attention
  • Stress levels
  • Medicines you take
  • Alcohol and drug use
  • Your personal and family history of depression and other mental health conditions

An example of a standardized questionnaire is the PHQ-9 Depression Scale. This is a nine-item questionnaire based on the diagnostic criteria for major depression. It can function as a screening tool, an aid to diagnosis, and a tool to track symptoms and overall depression severity over time.

Your health care provider will follow-up on these screening questions to get more detail related to your symptoms.

You may also have a physical exam. There’s no lab test that can diagnose depression; but your provider may order blood tests to find out if another health condition, such as anemia or thyroid disease, may be causing depression.

What is considered a comprehensive assessment?

As noted, a comprehensive assessment should include questions about your physical health, your medical history, what medications you’re taking, how you spend your time, and how you’re feeling. According to Ontario Health’s quality standard, a comprehensive assessment should also include the following:

  • Physical examination
  • Mental status examination – this is done through observation but also specific questions about your thoughts, perceptions, and behaviour
  • Relevant laboratory tests
  • Psychosocial history (including socioeconomic factors and trauma)
  • In some people, a more formal cognitive assessment or screening may be done (for more information about cognitive impairment view that topic)
  • Diagnosis of major depression using the criteria from the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition)
  • Use of validated tools for assessing the severity of symptoms and degree of functional impairment, such as the Patient Health Questionnaire (PHQ-9) or others
  • Assessment of potential medical and psychiatric co-existing conditions (especially bipolar disorder and symptoms of psychosis like delusions or hallucinations)
  • Past treatment history and complete medication history, including self-medication
  • Current and past substance use and addiction issues
  • Assessment of suicide risk and any suicidal thoughts that the person might be having.

The assessment should be done in a way that is respectful of diverse cultural, ethnic, and spiritual backgrounds. Information from the family and relevant third parties should be obtained when appropriate.

After other causes for depression like medical conditions or substances have been ‘ruled out’ or excluded you may be given the diagnosis of a major depression.

How is depression severity determined?

When you are diagnosed, your doctor may also specify whether your episode is mild, moderate, severe, or with psychotic features or with a seasonal pattern. Severity is based on the number of symptoms, the severity of those symptoms, and the degree of impact on everyday activities. Sometimes scoring on a standardized questionnaire like the PHQ-9 can also be used to estimate severity.

  • Mild: Few, if any, symptoms over-and-above what are needed to make the diagnosis, and the intensity of the symptoms and impact on function is still manageable.

  • Moderate: The number of symptoms, their intensity, and/or impact on everyday life are between “mild” and “severe.”

  • Severe: Many symptoms with a high degree of distress, and a marked impact on the ability to function.



Psychotherapy, antidepressants, and ECT.

What are the treatments for depression?

There are effective treatments for depression, including non-medication treatments like psychotherapy (‘talk therapy’) and medications, typically antidepressants. Choosing the right treatment plan should be based on a person’s individual needs and medical situation under a provider’s care. It may take some trial and error to find the treatment that works best for you. 

Treatment will also depend on a person’s preferences, the severity of their illness, associated symptoms, and availability/access to treatment options. In general, for a milder episode of major depression non-medication approaches may be recommended first. For moderate or severe depression many doctors recommend a combination of both medication and psychotherapy at the start of treatment.

Major depression is a serious illness associated with an increased risk of disability and death. People diagnosed with depression should typically receive treatment with antidepressants, psychotherapy, or both within 4 weeks for mild-moderate depression and within 7 days for severe depression.

Non-Medication Approaches

Talk therapy (also known as psychotherapy)

Psychotherapy (sometimes called talk therapy) refers to a variety of treatments that aim to help a person identify and change troubling emotions, thoughts, and behaviours. Even when medication relieves symptoms, psychotherapy can help a person address specific issues. These might include self-defeating ways of thinking, irrational fears, problems interacting with other people, or difficulty coping with situations at home, school, or work.

Common types of psychotherapy

Cognitive behavioural therapy (CBT) and interpersonal therapy (IPT) are the most common, best-evidence, psychotherapies for major depression. There are a few different variations on these types of therapy. They can be delivered on either a one-to-one or group basis; and are generally delivered over the course of about 12-20 sessions over 3 or 4 months (about an hour per session), though some have been designed for shorter durations such as 8 sessions. They are typically delivered by an appropriately trained therapist or physician in accordance with a treatment manual (validated, consistent approach to the therapy). CBT has also been shown to be effectively delivered remotely/virtually using technologies such as video conferencing (sometimes referred to as therapist-guided internet CBT or iCBT).

Benefits do not typically happen right away, so it’s important to give any form of psychotherapy enough time before determining whether or not it’s effective for you. Some people start to have initial benefits after 4-6 sessions, but full treatment of depression typically takes longer.

Finding a therapist

Consult your primary care provider if you are looking for a therapist. While some provinces and territories may provide psychotherapy as part of the provincial health plan, not all do. (Or it may be harder to access those that are funded by provincial or territorial health plans.)

‘Private’ psychotherapy can be quite expensive so, if you have private health insurance, check to see if your health insurance provider may have a list of recommended mental health professionals covered by your plan. If you are still employed and have benefits through work, check to see if your employer has some type of Employee Assistance Program (EAP or sometimes Employee Family Assistance Program or EFAP), which might include funding for a certain number of therapy sessions. Most EAP plans would not necessarily include a full course of evidence-based psychotherapy like CBT, though.

Once you have identified one or more possible therapists, a preliminary conversation can help you understand how treatment will proceed and decide if you feel comfortable with the therapist. It will also help to clarify if the therapist is using an evidence-based psychotherapy like CBT or IPT, and whether they’ve had specific training in those therapies.

Rapport and trust are essential. Discussions in therapy are deeply personal, and it’s important that you feel comfortable with the therapist and have confidence in their expertise.


A range of different self-management strategies can be effective complements to psychotherapy or medication treatments for depression, potentially resulting in faster and more complete improvement in symptoms. Pick ones that you like and that you think you can stick with.

  • Behavioural activation: While there are a wide range of definitions of ‘behavioural activation’, it is typically an approach to increasing a person’s involvement in pleasant events and activities. This may sound easy, but when someone’s depressed, it is hard to maintain interests and activities. Behavioural activation may involve deliberate scheduling of structured/regular activities, as well as other behavioural  strategies such as relaxation and stress reduction techniques, social skills enhancement, or creating specific activity or social goals. It’s been shown to reduce depressive symptoms in older people in the community. 
  • Yoga: This is a discipline that integrates physical postures, breath control, and meditation. The duration should be at least 4 weeks, with an average frequency of 4 sessions a week, and 45 to 60 minutes per session. 
  • Light therapy: This therapy involves daily exposure to bright light, usually administered at home with a fluorescent light box. The standard “dosage” of light is 10,000 lux (intensity) for 30 minutes per day, given early in the morning. This has been shown to be helpful for seasonal patterns of depression in winter.
  • Physical activity/exercise: Physical activity of any sort may be helpful for depression. Consistency is important, with most studies involving increased physical activity for at least 8 weeks, usually 3 times a week for 30 to 60 minutes per session. 
  • Sleep hygiene: The habits and practices of maintaining a regular sleep schedule; avoiding excess eating, drinking, or smoking before going to sleep; and establishing a proper sleep environment.
  • Nutrition: Maintaining a healthy, balanced diet and correcting any nutritional deficiencies.

For more information on nutrition, sleep, physical activity and Canada’s 24-hour movement guidelines view our content on promoting brain health.

Other self-help resources

There are many excellent online resources and programs. You can download a list of education and self-help resources, including websites, apps, books, and workbooks, from the resources areas for this topic (below and on the main topic landing page).

BounceBack is a free skill-building program from the Canadian Mental Health Association to help adults and youth 15+ to manage low mood, mild to moderate depression, anxiety, stress or worry. The programs are delivered online or over the phone with a coach. You will get access to tools to support you on a path to mental wellness. It is available in all provinces and territories. Visit

Wellness Together Canada is a free mental health and substance use resource that provides on-demand support; from basic wellness information, to one-on-one sessions with a counsellor, to participating in a community of support. Visit

Peer support groups are groups that connect you with others who have lived experience of major depression. You can find support groups through your local mood disorders association through the Mood Disorders Society of Canada website.

Mental health apps

There are many pros and cons to using mental health apps. Ultimately, you should discuss treatment plans with your doctor to find out if any mental health apps make sense as part of your treatment plan. Apps differ considerably in their main function, rigour of evaluation, costs, and privacy, so it’s very important to review any apps thoroughly before adopting them as part of your care plan. While some might be a helpful complement to evidence-based treatments, there is still not a lot of scientific research to recommend apps as the sole treatment for depression. At this time, probably their main purposes are for helping to monitor and track your depressive symptoms, and for specific apps that support mindfulness.

Pros of apps
  • Convenient – Treatment can take place anytime and anywhere
  • Anonymity (in some cases)
  • Good introduction to care 
  • Lower cost – Sometimes free or less expensive than a psychotherapy session with a mental health professional
  • 24-hour service
  • Consistency – Technology can offer the same treatment program to all users
  • Support – Technology can complement traditional therapy by extending an in-person session, reinforcing new skills, and providing support and monitoring.
Cons of apps
  • Guidance – There are no industry-wide standards to help consumers know if an app or other mobile technology is proven effective
  • Regulation – The question of who will or should regulate mental health technology and the data it generates needs to be answered
  • Effectiveness – Often limited or no scientific evidence that they work or that they work as well as traditional methods
  • Not for everyone – Some people may struggle with accessibility and usability of technology
  • Caution on Privacy – Personal information on an app raises concerns on guaranteed privacy
  • Overselling – Some apps may overpromise their results, which influences consumers to turn away from other, more effective therapies


Health care providers, such as a primary care provider or psychiatrist can prescribe medication for depression. The most common classes of medications used to treat depressive disorders are antidepressants. They don’t work immediately, and you may need to try more than one medicine before you can find the right one. However, in many cases medications do work faster than psychotherapy; and are frequently chosen as the first-line treatment for more severe depression.


Antidepressants are medications commonly used to treat depression. They take time to work—usually 4 to 8 weeks—and some depressive symptoms such as problems with sleep, appetite, or concentration often improve before mood improves. 

Just like it’s not fully understood what causes depression, it’s not fully understood how antidepressants work to treat depression. They may help improve the way your brain uses certain chemicals that control mood or stress. We don’t have any reliable way to determine in advance which antidepressant will work best for which person, so you may need to try several different antidepressant medicines before finding the one that improves your symptoms and has manageable side effects. A medication that has helped you or a close family member in the past will often be considered.

If you begin taking antidepressants, do not stop taking them without talking to your health care provider. Sometimes people taking antidepressants feel better and then stop taking the medication on their own, and the depression returns or they have withdrawal from stopping too quickly. Antidepressant medications are not considered to be addictive, but your brain and body do get used to them after a few weeks, so they shouldn’t be stopped ‘cold turkey’.

When you and your health care provider have decided it is time to stop the medication, usually after a course of at least 6-9 months of being well, your health care provider will help you slowly and safely decrease your dose. Stopping them abruptly can cause withdrawal symptoms; it has also been shown to increase the risk of relapse. 

Common antidepressants for major depression include selective serotonin reuptake inhibitors (or SSRIs) and serotonin and norepinephrine reuptake inhibitors (or SNRIs). While these medications are also known as “antidepressants,” they treat many different conditions, including anxiety disorders. In general, it is best to ‘start low and go slow’ with the dose of the medication; and know that your response to the medication may take a while, sometimes taking 4-6 or even 8 weeks for the start of symptom relief and up to 12 weeks or more for the medication to reach its full effect. It’s important to take your antidepressant medication as prescribed.

Some of the most commonly prescribed antidepressants include: escitalopram (Cipralex), mirtazapine (Remeron), sertraline (Zoloft), and venlafaxine (Effexor).

Because antidepressants can take several weeks to start working, it’s important to give the medication a chance before reaching a conclusion about its effectiveness.

With medication, longer-term therapy has been found to result in continued improvement in symptoms and helps to prevent relapse. For most people, medication therapy should be continued for at least 6-9 months after being well, depending on effectiveness and side effects. If your depressive symptoms have been more chronic, then your medication therapy should probably also last for longer to ensure a more complete and longer recovery period before considering tapering off of the medication. It’s important to try to treat all of your symptoms of depression; lingering symptoms may put you at an increased risk of relapse.

Many people who have had recurrent depression opt to stay on medication long-term; especially if they have had a good response and few side effects.

Side effects

Common side effects of SSRIs and other antidepressants may include upset stomach, headache, or sexual dysfunction. The side effects are generally mild and tend to improve over time. People who are sensitive to the side effects of these medications sometimes benefit from starting with a low dose, increasing the daily dose very slowly, and adjusting when they take the medication (for example, at bedtime or with food). Doctors often prescribe lower doses of antidepressants to older people, and increase the dose more slowly than in younger adults.

As with any medication, there are risks and benefits, and you should discuss these with your healthcare provider. It’s very important to discuss potential adverse effects of the various types of medications with your healthcare team.

In some cases, people may experience worsening anxiety or rarely even increased suicidal thoughts or behaviour when taking antidepressant medications, especially in the first few weeks after starting or when the dose is changed. Because of this, people of all ages taking antidepressants should be watched closely, especially during the first few weeks of treatment. More common side effects include headache, irritability/restlessness, nausea, and diarrhea. The most bothersome side effects according to patient surveys include sexual dysfunction, drowsiness, fatigue, and weight gain. Most side effects tend to occur during the first week or two of treatment as your body gets used to the new medication; many will resolve in that time, but some – like sexual side effects or weight gain – may persist throughout treatment.

Other types of medications that may be used in depression

Sometimes if your antidepressant is at the right dose and you’ve been taking it for long enough, but your still experiencing depressive symptoms, your doctor may add another medication to try to improve your treatment. This is sometimes called ‘adjunctive treatment’, and the second medication might be another antidepressant, lithium, or a different class of medications such as an atypical antipsychotic medication like quetiapine (Sertraline). While these medications were initially used to treat other mental illnesses, they’ve also been used to help manage depression for many years.

Choosing the Right Medication

There is not a lot of good-quality evidence at the moment to guide the selection of a specific antidepressant. Some types of drugs may work better for some patients, so people should work closely with a health care provider to identify which medication is best for them. Sometimes a medication may be chosen for potentially beneficial side effects; for example, if a medication is sedating or associated with increased appetite/weight gain, it might be a good choice for someone who is having problems with sleep and appetite. Or if a person has other medical conditions and is on other medications, it will be important to choose a medication that won’t aggravate any other conditions or have drug-drug interactions.

Choosing the right medication, medication dose, and treatment plan should be done under an expert’s care and should be based on a person’s needs and their medical situation. You and your provider may try several medicines before finding the right one.

Alternative treatments for depression

Brain stimulation therapy

Brain stimulation therapy, is also known as ‘neurostimulation’ or ‘neuromodulation’. The two main types of brain stimulation therapy are electroconvulsive therapy (ECT) and Repetitive Transcranial Magnetic Stimulation (rTMS).


ECT is considered one of the most effective treatments for severe depression. If medications do not reduce the symptoms of depression, ECT may be an option to explore. In some severe cases of depression where a rapid response is necessary or medications cannot be used safely, ECT can even be a first-line intervention.

Once strictly an inpatient procedure, today ECT is often performed on an outpatient basis. The treatment consists of a series of sessions, typically two-three times a week, for three to six weeks (usually 6-12 treatment sessions).

ECT may cause some side effects, including confusion, disorientation, and memory loss. Usually these side effects are short-term, but sometimes memory problems can linger, especially for the months around the time of the treatment course. 

Advances in ECT devices and methods have made modern ECT safe and effective for most patients.

ECT is not painful, and you cannot feel the electrical impulses. Before ECT begins, a patient is put under brief anesthesia and given a muscle relaxant. Within one hour after the treatment session, which takes only a few minutes, the patient is awake and alert.

After ECT, you are most likely to continue on an antidepressant medication to prevent a recurrence of depression. For some patients who respond well to ECT who haven’t found any medications that work effectively, ongoing less frequent treatments – maintenance ECT therapy – may be an option.


Repetitive transcranial magnetic stimulation (rTMS) uses a magnet to activate the brain. First developed in 1985, rTMS has been studied as a treatment for depression, psychosis, anxiety, and other disorders. Unlike ECT, in which electrical stimulation is more generalized, rTMS can be targeted to a specific site in the brain. Scientists believe that focusing on a specific site in the brain reduces the chance for the types of side effects associated with ECT. But opinions vary as to what site is best.

As a treatment, rTMS is typically reserved for major depression in patients who do not respond to at least one antidepressant medication. It is also used in other countries as a treatment for depression in patients who have not responded to medications and who might otherwise be considered for ECT. It doesn’t require anesthesia like ECT. The procedure tends to be well tolerated; the most common side effects include some discomfort at the site of the procedure and in the muscles of the jaw or mild headaches.

Key points from this topic

  • Psychotherapy (talk therapy) and antidepressant medications are both effective treatments for major depression.
  • The choice of which treatment or whether to use a combination depends on several factors including patient preference, availability/access, severity of depression, and co-occurring medical illnesses.
  • Psychotherapy and self-help might be the initial approach for a mild major depressive episode; while medications might be recommended for more severe depression, possibly in combination with psychotherapy.
  • The most common evidence-based psychotherapies to consider would be cognitive behavioural therapy (CBT) or interpersonal therapy (IPT). These may be supplemented with behavioural activation and other self-help techniques like increased physical activity.
  • There are a wide range of antidepressant medications. The most commonly prescribed first-line antidepressants are SSRIs and SNRIs.
  • Work with your doctor to determine if a medication makes sense to treat your depression, and to select the right medication for you.
  • Antidepressants don’t work right away, so it’s important to give the medication enough time to be effective.
  • Don’t stop antidepressants suddenly: you can have side effects if you discontinue rapidly, and it increases the risk of relapse. Work with your doctor if you do decide to come off of your medications, so you can do it safely.
  • In some circumstances, especially if your depression is very severe and life-threatening, a brain stimulation treatment like ECT may be an option.


Other Info

Additional information about follow-up, questions to ask your health care provider, and more.

What type of follow-up can I expect?

People with major depression are monitored for any suicidal thinking before and during treatment.

People with major depression should have a follow-up appointment with their health care provider at least every 2 weeks for at least 6 weeks or until treatment adherence and response have been achieved. After this, they have a follow-up appointment at least every 4 weeks until they enter remission (absence of depressive symptoms).

Keeping track of your medications

  • Make a list. Write down all the medicines you take, including over the counter drugs. Also include any vitamins or dietary supplements. The list should include the name of each medicine or supplement, the amount you take, and time(s) you take it. If it’s a prescription drug, also note the doctor who prescribed it and the reason it was prescribed. Show the list to all your health care providers, including physical therapists and dentists. Keep one copy in a safe place at home and one in your wallet or purse.
  • Get familiar with your medicines. If you take more than one medicine, make sure you can tell them apart by size, shape, color, or the number imprinted on the pill.
  • Create a file. Save all the written information that comes with your medicines and keep it somewhere you can easily refer to it. Keep these guides for as long as you’re taking the medication.
  • Check expiration dates on bottles. Don’t take medicines that are past their expiration date. Your doctor can tell you if you need a refill.
  • Secure your medicines. Keep your medicines out of the reach of children and pets. If you take any prescription pain medicines (for example, morphine, other opioids, or codeine), keep them in a locked cabinet or drawer. If your medicines are kept in bottles without safety caps because those are hard for you to open, be extra careful about where you store them.
  • Dispose of your medicines safely. Check the expiration dates on your medication bottles and discard any unused or expired medicines as soon as possible. Timely disposal of medicines can reduce the risk of others taking them accidentally or misusing the medications on purpose. Check with your doctor or pharmacist about how to safely discard expired or unneeded medications.

Download this worksheet from the National Institute on Aging.

How can I prevent this condition?

  • If you are diagnosed with depression, take your medicine exactly as your provider instructed. Learn to recognize the early signs that your depression is getting worse.
  • Keep going to your talk therapy sessions.
  • DO NOT drink alcohol or use illegal drugs. These substances make depression worse and may lead to thoughts of suicide.

Beyond Treatment: Things You Can Do

Here are other tips that may help you or a loved one during treatment for depression:

  • Try to get some physical activity. Just 30 minutes a day of walking can boost mood.
  • Try to maintain a regular bedtime and wake-up time.
  • Eat regular, healthy meals.
  • Do what you can as you can. Decide what must get done and what can wait.
  • Try to connect with other people, and talk with people you trust about how you are feeling.
  • Postpone important decisions, such as getting married or divorced, or making a big move until you feel better.

What should I ask my health care provider?

Tips to talking with your healthcare provider:

  • Prepare questions, a list of your medications and review your family history
  • Bring a friend or relative
  • Be honest
  • Ask questions

Ask yourself these questions and note down your answers. Bring these answers to your appointment with your healthcare provider:

  • Which symptoms bother you most? Some antidepressants may do a better job helping specific symptoms, such as trouble sleeping.
  • What other medicines and supplements do you take? Some antidepressants can cause problems if you take them with certain medicines and herbs.
  • Did a certain antidepressant work well for a close relative? An antidepressant that helped a parent, brother, or sister could be a good choice for you, too.
  • Do you have other health conditions? Certain antidepressants can make some other conditions better or worse. Any other conditions that you have will be part of choosing your depression treatment.
  • What is the name of the medicine and why am I taking it?
  • Is there a less expensive alternative?
  • When should I expect the medicine to start working? How will I know if it’s working?
  • What type of side effects might I expect, if any? What should I do if I experience serious side effects?
  • Will this drug cause problems if I am taking other prescriptions, OTC (over the counter) medicines, or supplements?
  • What should I do if I want to stop taking this medicine? Is it safe to stop abruptly?
  • Will I need a refill? If so, will I need a follow-up appointment or other testing before I can refill the medication?
  • How long will I need to take an antidepressant?

How can I help a loved one who is depressed?

If someone you know has depression, help them see a health care provider or mental health professional. You also can:

  • Offer support, understanding, patience, and encouragement.
  • Invite them out for walks, outings, and other activities.
  • Help them stick to their treatment plan, such as setting reminders to take prescribed medications.
  • Make sure they have transportation to therapy appointments.
  • Remind them that, with time and treatment, the depression will lift.

Take comments about suicide seriously, and report them to your loved one’s health care provider or therapist. If they are in immediate distress or thinking about hurting themselves, call 911 for emergency services or go to the nearest hospital emergency room.

Where can I get help? Where can my family get support?

If you or someone you know is in crisis:

  • If you’re in immediate danger or need urgent medical support, call 911 or go to your nearest hospital or emergency department
  • Talk Suicide Canada
    • Call 24/7/365 Toll free at 1-833-456-4566
    • Text 45645 between 4pm – midnight eastern time
  • Visit Talk Suicide Canada for the distress centres and crisis organizations nearest you.
  • Hope for Wellness Help Line (Indigenous)
    • Call 1-855-242-3310 (toll-free) or connect to the online Hope for Wellness chat.
    • Available 24 hours a day, 7 days a week to First Nations, Inuit, and Métis Peoples seeking emotional support, crisis intervention, or referrals to community-based services.
    • Support is available in English and French and, by request, in Cree, Ojibway, and Inuktitut.
  • For residents of Quebec, call 1-866-277-3553 or visit

Ontario-specific mental health support

  • 211 Ontario
    • Information and referral for community, government, social and health services, including mental health resources across Ontario.
    • Call 2-1-1
    • Toll-free: 1-877-330-3213
    • Live web chat
    • Email
  • ConnexOntario Helpline

Where can I find out more information?

See our resources below and on the depression landing page.



Putting it all together.

Key points about this topic

  • Major depression is a persistent overwhelming feeling of sadness and other symptoms that lasts for at least two weeks.
  • You should see your health care provider if you’ve been showing signs and symptoms of depression.
  • A comprehensive assessment of depression involves a health care provider taking a detailed history of your symptoms and current stressors, as well as your medical history, any medications your taking, substance use, your previous history of mental health issues, and your family psychiatric history. It may also include the use of standardized questionnaires, physical examination, and lab tests if needed, to rule out other medical causes of depression.
  • If the diagnosis is confirmed, your health care provider will talk with you about evidence-based treatments, such as CBT or antidepressant medications. There are also things you can do for yourself to help, like behavioural activation techniques, exercise/physical activity, yoga, or light therapy.
  • Follow up is important to ensure that you are responding to your treatment, and that you eventually fully recover.
  • Most people need maintenance treatment for at least 6-9 months; and possibly longer if the depression has been more chronic.

About this page

This page was developed by the Division of e-Learning Innovation team and Dr. Anthony J. Levinson, MD, FRCPC (Psychiatry). Dr. Levinson is a psychiatrist and professor in the Department of Psychiatry and Behaviour Neurosciences, Faculty of Health Sciences, McMaster University. He is the Director of the Division of e-Learning Innovation, as well as the John Evans Chair in Health Sciences Educational Research at McMaster. He practices Consultation-Liaison Psychiatry (psychiatry of the medically ill), with a special focus on dementia and neuropsychiatry. He is also the co-developer of the dementia care partner resource, and one of the co-leads for the McMaster Optimal Aging Portal. He and his team are passionate about developing high-quality digital content to improve people's understanding about health. By the way, no computer-generated content was used on this page. Specifically, a real human (me) wrote and edited this page without the help of generative AI like ChatGPT or Bing's new AI or otherwise.

Initially published in February 2023. Last reviewed February 28, 2023.

Dr. Levinson receives funding from McMaster University as part of his research chair. He has also received several grants for his work, from not-for-profit granting agencies. He has no conflicts of interest with respect to the pharmaceutical industry; and there were no funds from industry used in the development of this website.

Content was written and adapted based on credible, high-quality, non-biased sources such as MedlinePlus, the National Institutes for Mental Health, the McMaster Optimal Aging Portal, the American Psychiatric Association, the Cochrane Library, the Centre for Addictions and Mental Health (CAMH), Canadian Network for Mood and Anxiety Treatments (CANMAT), Health Quality Ontario Quality Standard, and others. See References below for additional details.

Funding was provided by the Labarge Optimal Aging Initiative and in-kind contributions from McMaster University and CAMH. There was no industry funding for this content.

Curated Resources

Helpful Links and Resources

Expert-selected websites and documents related to depression.

Patient and Family Guide to Depression Treatment

Based on the CANMAT 2016 Clinical Guidelines, this PDF provides an overview of treatment options.

View Resource

Health Quality Ontario Patient Reference Guide

HQO Quality Standard patient reference guide for major depression.

View Resource

Mood Disorders Society of Canada

Links to National, Provincial, and Territorial Organizations.

View Resource

Find Canadian Mental Health Association

Find CMHA in your area.

View Resource


BounceBack is a free program from the CMHA that helps you build skills to improve your mental health.

View Resource
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Evidence-based references that informed this topic.

About this Topic

This content was developed by the Division of e-Learning Innovation in the Faculty of Health Sciences, McMaster University. It was authored, reviewed, and assessed for accuracy by psychiatrist Dr. Anthony J. Levinson from McMaster. There are no conflicts of interest.

The development process included a review of the Canadian Network for Mood and Anxiety Treatments (CANMAT) Guidelines for depression; the American Psychiatric Association Clinical Practice Guideline on Depression; and Health Quality Ontario’s Quality Standard and Patient Guide on Major Depression.

If you have questions or comments related to this resource, please contact us at

Core References

  1. Health Quality Ontario. Patient Reference Guide: Major Depression- Care for Adults and Adolescents; 2016. Accessed February 27, 2023.
  2. Health Quality Ontario. Quality Standard: Major Depression. Accessed February 27, 2022.
  3. CANMAT 2016 Depression Guidelines and The CHOICE-D Patient and Family Guide to Depression Treatment. Accessed February 27, 2023.
  4. CAMH. Depression in Older Adults. Accessed February 27, 2023.
  5. MedlinePlus [Internet]. Bethesda (MD): National Library of Medicine (US); [updated 2020 Jun 24]. Depression; [updated 2016 Nov 4; cited 2023 Feb 27]. Available from:
  6. National Institute of Mental Health (2021). Depression. U.S. Department of Health and Human Services, National Institutes of Health. Retrieved February 27, 2023, from
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