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.

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.

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.

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.

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.

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.

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.

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.