Major depressive disorder (MDD), also known simply as depression, is a mental disorder characterized by at least two weeks of low mood that is present across most situations. Low self-esteem, loss interest in activities that are normally enjoyable, low energy and pain can all be signs of major depressive disorder . Sometimes, people may have false beliefs and hear or see things others cannot. *Some people experience depression for a few years, while others have depression that lasts several years. However, some people are more depressed than others. Major depression disorder can have a negative impact on a person’s life, work and school, as well their sleeping habits, eating habits, general health, and overall health.  Between 2-7% of adults with major depression die by suicide, and up to 60% of people who die by suicide had depression or another mood disorder.
It is thought that the cause of the condition may be genetic, psychological, and environmental factors. Risk factors include family history, major life events, medication, chronic health problems, substance abuse, and certain medications.  About 40% of the risk appears to be related to genetics.  Major depressive disorder diagnosis is made based on the patient’s experiences and a mental state examination.  Major depression is not diagnosed by a laboratory.  Testing may be performed to rule out other conditions that could cause similar symptoms.  Major Depression should be distinguished from sadness. This is a normal part in life and is usually less severe.  The United States Preventive Services Task Force (USPSTF) recommends screening for depression among those over the age 12, while a prior Cochrane review found that the routine use of screening questionnaires have little effect on detection or treatment.
People are usually treated with antidepressant medication and counseling.  Although medication appears to be effective in some cases, it may not be as effective for all.  There is no way to know if medications have an effect on suicide risk.  There are two types of counseling: cognitive behavioral therapy (CBT), and interpersonal therapy.  If all other methods fail, electroconvulsive treatment (ECT) can be used. Hospitalization is sometimes necessary for people who are at risk of self-harm and can be against their wishes.
Major depressive disorder affected approximately 216 million people (3% of the world’s population) in 2015.  The percentage of people who are affected at one point in their life varies from 7% in Japan to 21% in France.  Lifetime rates are higher in the developed world (15%) compared to the developing world (11%). It is the most common cause of disability, after low back pain.  The most common time of onset is in a person in their 20s and 30s. Females are affected about twice as often as males.  The American Psychiatric Association added “major depressive disorder” to the Diagnostic and Statistical Manual of Mental Disorders (DSM-III) in 1980.  This was a division of the previously depressive neurosis (DSM-II) which also included the conditions dysthymia, adjustment disorder with depression mood and dysthymia.  People who are currently affected or have been previously may be stigmatized.
There are many types of depression. They range from mild, brief episodes of sadness to persistent, severe depression. Major depression, or major depressive disorder, is the most severe form of depression. It’s not the same as depression that is caused by loss (e.g. the death of a close friend) or by medical conditions like a thyroid condition.
Many doctors use the Diagnostic and Statistical Manual of Mental Disorders (5 (DSM-5) to diagnose clinical depression. This manual is published by the American Psychiatric Association.
These symptoms can cause significant problems in relationships or daily activities such as school, work, or social life.
Anyone can experience clinical depression, even children. Even if the depression is severe, symptoms of clinical depression can be treated with antidepressant medication, psychological counseling, or a combination.