Major depressive disorder

Major depressive disorder, also known as major depression, unipolar depression, clinical depression, or simply depression, is a psychiatric disorder characterized by a pervasive low mood, loss of interest in a person's usual activities and diminished ability to experience pleasure. The diagnosis is made if a person has suffered one or more major depressive episodes. The onset is usually in early- to mid-adulthood. Diagnosis is based on the patient's self-reported experiences and observed behavior; there is no laboratory test for major depression. The course varies widely: it can be a once-in-a-lifetime event or have multiple recurrences; it can appear either gradually or suddenly; and can either last for a few months or be a life-long disorder.
Although the term "depression" is commonly used by laypeople to describe a temporary depressed mood, when a person may feel sad or "down", major depression is a serious and often disabling condition that can significantly affect a person's work, family and school life, sleeping and eating habits, general health and ability to enjoy life.[1] Depression is a major risk factor for suicide; in addition, people with depression suffer from higher mortality from other causes.[2] Clinical depression may be isolated or be a secondary result of a primary condition such as bipolar disorder or chronic pain. When specific treatment is indicated, it usually consists of psychotherapy and antidepressants.

Signs and symptoms

A major depressive episode can manifest with a variety of symptoms, but almost all patients display a marked change in mood, a deep feeling of sadness, and a noticeable loss of interest or pleasure in favorite activities. Other symptoms include:
Persistent sad, anxious or "empty" mood Loss of appetite and/or weight loss or conversely overeating and weight gain Insomnia, early morning awakening, or oversleeping Restlessness or irritability Psychomotor agitation or psychomotor retardation Feelings of worthlessness, inappropriate guilt, helplessness Feelings of hopelessness, pessimism Difficulty thinking, concentrating, remembering or making decisions Thoughts of death or suicide or attempts at suicide Loss of interest or pleasure in hobbies and activities that were once enjoyed Withdrawal from social situations, family and friends Decreased energy, fatigue, feeling "slowed down" or sluggish Persistent physical symptoms that do not respond to treatment, such as headaches, digestive problems, and chronic pain Not all patients will suffer from every symptom. The severity of symptoms will vary widely among individuals. Symptoms must, however, persist for at least two weeks before being considered a potential sign of depression, with the exception of suicidal thoughts or attempts
Diagnosis of an episode in children is more difficult than in adults and is often left undiagnosed, and thus untreated, because the symptoms in children are often written off as normal childhood moodiness. Diagnosis is also made difficult because children are more likely than adults to show different symptoms depending on the situation
While some children still function reasonably well, most who are suffering depression will suffer from a noticeable change in their social activities and life, a loss of interest in school and poor academic performance, and possibly drastic changes in appearance. They may also begin abusing drugs and/or alcohol, particularly past the age of 12. Although much more rarely than adults, children with major depression may attempt suicide or have suicidal thoughts even before the