Major depressive disorder

Major depressive disorder is defined by the DSM as having one or more major depressive episodes which is a period of two weeks or more where a person has either
*depressed mood (can be irritable in children) or
*the loss of interest or pleasure in nearly all activities
and may also have the following symptoms (at least 5 or more) nearly every day:
*depressed (or irritable for children) mood by a person's own report or as observed by others
*significantly diminished interest or pleasure in all, or almost all, activities most of the day
*significant change in weight (not due to dieting) or appetite
*insomnia or hypersomnia
*observable physical agitation or lethargy
*fatigue or loss of energy
*feelings of worthlessness or excessive or inappropriate guilt
*having difficulty thinking clearly or concentrating or indecisiveness
*regular thoughts of death or suicide (either unplanned, planned, or attempted)
To meet clinical standards these symptoms also must cause significant distress or impairment in social, occupational, or other important areas of functioning.
The condition is also not caused or explained by the following:
*Due to effects of drugs or medication
*Due to a medical condition
*Better explained as bereavement
This diagnosis is not used if the person has had any of the following:
*Manic episode - see Bipolar I disorder instead
*Mixed episode - see Bipolar I disorder instead
*Hypomanic episode - see Bipolar II disorder instead
*Psychosis - see Psychotic disorders instead