Types of depression

Clinical or major depression is an illness characterized by a cluster of feelings, thoughts, and behaviours that are strikingly different from a person's normal range of feelings and functioning. Caused by a complex interaction of biological, social and psychological factors, a major depressive disorder can make people exquisitely sensitive to life circumstances, the least of which can throw them into total black despair.
Major depression affects all areas of your life--your family, your job, and social relationships and situations--and can make other medical problems worse.
During a major depression, a person becomes enveloped by feelings of sadness, emptiness and worthlessness. Like an impenetrable curtain descending, these feelings distort every thought and experience, rendering life meaningless and hopeless. Feelings of being deeply, continually deprived, insignificant, inadequate and guilt-ridden build on feelings of sadness. At the same time, a depressed person may feel chronically irritated, occasionally erupting in frustration and anger.
While a major depression may be triggered by some life circumstance or event, the mood reaction seems greatly exaggerated. In all likelihood, depression has less to do with events that occur than with an individual's inherent vulnerability to the condition.
In rare cases, a person may experience a major depression as a single episode. However, in most instances, clinical depression tends to recur periodically, reactively or cyclically. A major depression may last up to two years.

Mild depression is a type of depression where you have some symptoms of depression and it takes some extra effort to keep up with the demands of your job and personal life, but you're able to function in your everyday life. This form of depression often resolves on its own after a few weeks or months without therapy.
Moderate depression is a type of depression in which you have many symptoms of depression and you have trouble doing the things you need to do. Like mild depression, moderate depression often goes away on its own without treatment. Treatment, however, will help you function better and may speed your recovery.

Dysthymic Disorders are milder depressive states that last two years or more. It is likely that these low-grade, intermittent or chronic depressive states form in some people the temperamental basis from which major depressions arise. For those with dysthymic disorder, certain life circumstances - the end of a relationship, the loss of a job, going away to college, for example - might provoke a deeper depression. Most people with dysthymia can't tell for sure when they first became depressed. People with dysthymic disorder may have periods of normal mood that last up to 2 months. Family members and friends may not even know that their loved one is depressed. Even though this type of depression is mild, it may make it difficult for a person to function at home, school or work.

Manic depression is a form of depression where a person has periods of depression followed by periods of intense elation or mania. This is also called bipolar depression or bipolar disease.

Seasonal affective disorder. For some people, there is a seasonal aspect to their depression. Seasonal affective disorder (SAD) is a form of depression in which symptoms develop every winter. SAD is thought to be related to the reduced amount of sunlight available during the winter months. It is characterized by fatigue, carbohydrate craving, overeating and oversleeping.

Postnatal or postpartum depression describes the feelings of sadness that occur after the birth of a child. Postpartum depression is fairly common. It usually goes away after a few days or weeks, although in some cases it can be serious and requires treatment.