Depressive disorders come in different forms, just as do other medical illnesses. The most common types of depression are:

Major Depression: Major depression is manifested by a combination of symptoms (that interfere with the ability to work, sleep, eat; and enjoy once-pleasurable activities. These disabling episodes of depression can occur once, twice, or several times in a lifetime.

Dysthymia: Dysthymia is chronic mild to moderate chronic depression, as opposed to major depression. The DSM-IV mandates the same symptoms as for major depression, except for suicidality, but requires only three symptoms in all, so long as they have persisted over two years.

Bipolar Depression: Bipolar depression is a feature of bipolar disorder, also known as manic depression, an illness characterized by mood swings from depression to mania. When in the depressed cycle, you can have any or all of the symptoms of a depressive disorder.

Melancholic Depression: Melancholic depression is major depression with an emphasis on lack of pleasure or lack of reactivity to pleasure. Other characteristics include (three or more): Depressed mood, depression at worst in the morning, early morning awakening, psychomotor agitation or retardation, significant weight loss, and inappropriate guilt.

Atypical Depression: Atypical depression is major depression that differs from melancholic depression in that patients react positively to external events, plus (two or more): Significant weight gain (as opposed to weight loss), hypersomnia (as opposed to insomnia), leaden paralysis, and sensitivity to personal rejection.

Seasonal Affective Disorder (SAD): SAD is a pattern of depressive illness in which symptoms recur every winter. This form of depressive illness often is accompanied by such symptoms as marked decrease in energy, increased need for sleep, and carbohydrate craving.

Postpartum Depression: Mild moodiness and "blues" are very common after having a baby, but when symptoms are more than mild or last more than a few days, help should be sought. Post-partum depression can be extremely serious for both mother and baby.

Endogenous Depression: A depression is said to be endogenous if it occurs without a particular bad event, stressful situation or other definite, outside cause being present in the person's life.

Adjustment Disorder with Depressed Mood: This is the type of depression that results when a person has something bad happen to them that depresses them. For example, loss of one's job can cause this type of depression. It generally fades as time passes and the person gets over what ever it was that happened.