Major depression, also called unipolar depression, which is the most common type of depression. It tends to be episodic, but can persistently recur. Symptoms must persist for at least two weeks.
Dysthymia, which is a chronic, unremitting depression. A dysthymia diagnosis requires fewer symptoms than major depression, but must be present for at least two years.
Bipolar disorder, also called manic depression, which is depression alternating with elated or irritable moods and increased energy.
Major depression and dysthymia is twice as prevalent among women than men: 1 in 4 women and 1 in 8 men will experience these types of depression at some point in their lives.
Many factors can cause depression, including biochemistry (a chemical imbalance of mood regulation in the brain), genetics, family history, substance abuse, and an illness or other difficult life events. Some people have mild depression, while in others depression is more severe.
Regardless of the cause, a person should be treated for depression. One-half of people with depression do not seek treatment because they don't understand their symptoms or have fear of the stigma of mental illness. Yet of those who do, 80% are treated effectively with medication, psychotherapy, or both.