Depressive disorders are a type of mood disorder that include a number of conditions. They are all characterized by the presence of sad, empty, or irritable moods accompanied by physical and cognitive symptoms. They differ in terms of duration, timing, or presumed etiology.

• Disruptive mood dysregulation disorder: A childhood condition characterized by extreme anger and irritability. Children display frequent and intense outbursts of temper.
• Major depressive disorder: A condition characterized by loss of interest in activities and depressed mood which leads to significant impairments in how a person is able to function.
• Persistent depressive disorder (dysthymia): This is a type of ongoing, chronic depression that is characterized by other symptoms of depression that, while often less severe, are longer lasting. Diagnosis requires experiencing depressed mood on most days for a period of at least two years.
• Other or unspecified depressive disorder: This diagnosis is for cases when symptoms do not meet the criteria for the diagnosis of another depressive disorder, but they still create problems with an individual’s life and functioning.
• Premenstrual dysphoric disorder: This condition is a form of premenstrual syndrome (PMS) characterized by significant depression, irritability, and anxiety that begins a week or two before menstruation begins. Symptoms usually go away within a few day’s following a woman’s period.
• Substance/medication-induced depressive disorder: This condition occurs when an individual experiences symptoms of a depressive disorder either while using alcohol or other substances or while going through withdrawal from a substance.
• Depressive disorder due to another medical condition: This condition is diagnosed when a person’s medical history suggests that their depressive symptoms may be the result of a medical condition. Medical conditions that may contribute to or cause depression include diabetes, stroke, Parkinson’s disease, autoimmune conditions, chronic pain conditions, cancer, infections and HIV/AIDS.

The depressive disorders are all characterized by feelings of sadness and low mood that are persistent and severe enough to affect how a person functions. Common symptoms shared by these disorders include difficulty feeling interested and motivated, lack of interest in previously enjoyed activities, sleep disturbances, and poor concentration.

The diagnostic criteria vary for each specific condition.

For major depressive disorder, diagnosis requires an individual to experience five or more of the following symptoms over the same two-week period. One of these symptoms must include either depressed mood or loss of interest or pleasure in previously enjoyed activities.

Symptoms can include:

• Depressed mood for most or all of the day
• Decreased or lack of interest in activities the individual previously enjoyed
• Significant weight loss or gain, or decreased or increased appetite
• Sleep disturbances (insomnia or hypersomnia)
• Feelings of slowed physical activity or restlessness
• Lack of energy or fatigue that lasts most or all of the day
• Feelings of guilt or worthlessness
• Difficulty thinking or concentrating
• Preoccupation with death or thoughts of suicide