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*Please note: This slide show represents a visual interpretation and is not indicative of clinical effectiveness. Please consult your physician for any medical conditions.
Mood disorders include psychological conditions like major depression and bipolar disorder, which can have a major impact on a person’s work, family and social life.
Major depressive disorder (MDD) is different from other forms of depression because it tends to be a very severe form of depression that is persistent and adversely affects daily living.
Usually MDD is triggered by experiences in life, such as loss. Unlike traumatic grief or bereavement, in which people may cry a lot but over time can begin to move on with their lives, in MDD, people may also cry a lot, but they cry about anything that doesn't necessarily have to do with any loss.
Typically, MDD has to do with the chemistry of the brain and is usually also connected to a person's genetic history.
Seen here, is a network of nerve cells in the brain, called neurons.
These neurons pass on messages, or signals of information, within the brain.
This allows the brain to communicate with parts of the body to produce muscle movement, speak words or to experience feelings.
If we zoom further onto these neurons, we see that a small gap between their endings, called the synaptic cleft, exists.
To carry messages from one neuron to the next, brain chemicals called neurotransmitters, are involved in communicating brain signals across this space.
Overall, this junction between two neurons is called a synapse.
In people with major depression, signal traffic within the brain is reduced.
This may relate to the symptoms of MDD.
The goal of MDD therapy is to restore healthy functioning of the brain and to help patients restore their quality of life.
There are several types of treatment options available for MDD and your doctor can help explain and discuss the benefits and side-effects of each with you.
Some treatment options that may be discussed include:
  • Therapeutic counselling;
  • Lifestyle modifications, such as: Exercise, a balanced diet, regular hours of sleep, reducing stress, and a stop to smoking, alcohol, and recreational drugs;
  • Antidepressant medications, such as: Tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), and serotonin-norepinephrine reuptake inhibitors (SNRIs);
  • and lastly, electroconvulsive shock therapy (ECT).
Since the chosen treatment option - or combination of options - will differ among patients, it is important to work with your doctor in order to learn which therapies will be most suitable for you.
Slide Show - Understanding Depressive Disorder

Major Depressive Disorder (MDD) is one of several mood disorders that can affect all aspects of your life—health, friendships, family relationships, work and more. This slide show explains how genetics, changes in the brain, and stressful events can cause a mood disorder such as MDD.

Animation - Understanding Depressive Disorder

This animation explains how Major Depressive Disorder (MDD) is defined as one of several mood disorders that can negatively affect all aspects of your life. MDD is usually triggered by experiences in life such as loss of a loved one, however unlike normal bereavement, people with MDD are unable to move on with their life. MDD appears to affect the chemistry of the brain and can usually be linked to a family genetic history.

Animation - Understanding the chemistry of the brain

This animation explains how the brain works and how changes in brain chemistry can affect mood, health and day-to-day living. The brain has cells called neurons that carry messages or signals from one part of the brain to other parts of the brain or body. Brain chemicals called neurotransmitters are involved in communicating messages from one neuron to the next. In MDD it is believed that there is an imbalance in these brain chemicals.

Expert Video - What are mood disorders and what is a depressive disorder?

Depression, or a depressive disorder, is a type of mood disorder. Mood disorders include MDD, bipolar disorder and seasonal affective disorder, among others. More than just a bad day or two, all of them can affect your social, family, school and work life. As our experts, Dr. Anker and Dr. Marshall, explain in this video, mood disorders can last for a week or two or may persist for several months or years.

Expert Video - How is MDD different from other types of depression?

While major depressive disorder (MDD) is like other mood or depressive disorders in many ways, it tends to be much more serious and cause more difficulty in daily life. A death or job loss or divorce may trigger MDD in someone who has a genetic inclination to depression. In other people, the same events may make them very sad and tearful for a while, but then they carry on with their lives. If you have MDD, you may cry over almost anything and moving on with your life can be very difficult. Other kinds of depression include a low-level, long-lasting depression called dysthymia (which people may not even recognize as abnormal), depression caused by medical conditions or medicines, and premenstrual dysphoric disorder.

Expert Video - What are the risks of MDD?

MDD can make you feel sad or hopeless and increase your risk of suicide. Drs. Anker and Marshall also explain in this video that if you suffer from it for a long time, it can increase your risk of dying from heart disease and developing many other diseases, too.

Expert Video - What risk factors and triggers are likely to cause MDD?

In this video discussion, Dr. Anker and Dr. Marshall discuss the genetic and environmental factors that put people at risk for major depressive disorder (MDD). Some people seem to be able to face one problem after another and never lose sleep, lose hope, lose energy or feel depressed. They can’t become depressed because they do not have the brain chemistry or genetics for it. Other people inherit a predisposition for depression. That means that if you have MDD, you probably have close relatives who had depression or another mood disorder. For people with a family tendency to depression, an illness, job loss or divorce can trigger MDD. For others, severe depression can occur without any clear cause. If you have MDD, no matter what caused it, you need to get treatment just as you would for any other serious illness, by contacting your healthcare provider.

Expert Video - The brain’s role in MDD

While we don’t know exactly what causes depression, we know that something goes wrong with the communication among nerve cells via their neurotransmitters - the messenger signals - in the brain. A problem with these signals from nerve cells quickly causes more problems because each nerve cell stimulates 10,000 other nerve cells in the brain. Each of those cells have four or more waves of reaction. We are just starting to understand how those changes in the brain cause what we see as the symptoms of depression.