What are the different forms of depression?

    There are several forms of depressive disorders. The most common are major depressive disorder and dysthymic disorder.

    Major depressive disorder, also called major depression, is characterized by a combination of symptoms that interfere with a person's ability to work, sleep, study, eat, and enjoy once–pleasurable activities. Major depression is disabling and prevents a person from functioning normally. An episode of major depression may occur only once in a person's lifetime, but more often, it recurs throughout a person's life.

    Dysthymic disorder, also called dysthymia, is characterized by long–term （two years or longer） but less severe symptoms that may not disable a person but can prevent one from functioning normally or feeling well. People with dysthymia may also experience one or more episodes of major depression during their lifetimes.

    Some forms of depressive disorder exhibit slightly different characteristics than those described above, or they may develop under unique circumstances. However, not all scientists agree on how to characterize and define these forms of depression. They include:

    Psychotic depression, which occurs when a severe depressive illness is accompanied by some form of psychosis, such as a break with reality, hallucinations, and delusions.

    Postpartum depression, which is diagnosed if a new mother develops a major depressive episode within one month after delivery. It is estimated that 10 to 15 percent of women experience postpartum depression after giving birth.

    1. Seasonal affective disorder （SAD）, which is characterized by the onset of a depressive illness during the winter months, when there is less natural sunlight. The depression generally lifts during spring and summer. SAD may be effectively treated with light therapy, but nearly half of those with SAD do not respond to light therapy alone. Antidepressant medication and psychotherapy can reduce SAD symptoms, either alone or in combination with light therapy.

    2. Bipolar disorder, also called manic-depressive illness, is not as common as major depression or dysthymia. Bipolar disorder is characterized by cycling mood changes-from extreme highs （e.g., mania） to extreme lows （e.g., depression）. Visit the NIMH website for more information about bipolar disorder.

    抑郁癥有幾種類型。最常見的是重度抑郁癥和心境惡劣障礙。

    重度抑郁癥，也叫做重度抑郁，以一組妨礙個體的工作、睡眠、學習、飲食和享樂（一度愉悅的活動）的癥狀為特色的疾病。重度抑郁能致殘并使個人正常機能受損。重度抑郁發作可能在個體一生中僅出現一次，但是更多的情況是重度抑郁在一生中反復發作。

    心境惡劣障礙，也叫做惡劣心境，以長期（兩年或更長）但是較輕的癥狀為特色。它并不一定使個人致殘，但是能使個人正常機能受損或不能感到心情舒服。心境惡劣患者在其一生中，也會經歷一次或更多此的重度抑郁。

    一些抑郁癥形式在表現上與上述障礙相比，稍有不同的特征；或者，它們可能在特定的環境下患上。但是，并不是所有科學家都同意如何對這些形式的抑郁癥的定義和分類。它們包括：

    精神病性抑郁癥，這種疾病會出現，當重度抑郁癥伴隨有一些精神病形式，比如喪失現實感、幻覺和妄想。

    產后抑郁癥，如果新生兒母親在分娩一個月后重度抑郁癥發作，那么該病便確診了。我們估計10-15%的女性在生產后，經歷重度抑郁癥。

    季節性情緒紊亂癥（SAD）,以冬季缺乏自然光，抑郁癥發作為特色的。抑郁通常在春季和夏季消褪。SAD患者可能對光線療法有效，但是幾乎一半的SAD患者對單用光線療法無反應。抗抑郁藥物和心理療法可以減少SAD癥狀。它們要么單獨使用，或者與光線療法聯用。

    雙相情感障礙，也叫做躁郁癥，并不像重度抑郁癥或心境惡劣一樣普遍。雙相情感障礙是以環性心境變化--從高峰（比如，躁狂）到低谷（比如，抑郁）為特色的。請參看NIMH網站獲得更多關于雙相情感障礙的信息。