The diagnosis of depression in clinical settings involves four aspects:

First, the collection of medical history, which includes understanding the onset, progression, treatment, and outcome of the illness, as well as past treatment experiences, etc.

Second, psychiatric assessment, involving examinations with the patient concerning their sensations, perceptions, consciousness, thinking, emotions, intelligence, memory, self-control, willpower, and other aspects.

Third, the use of scales to measure depression, which includes self-rating scales or observer-rating scales for depression to assess the severity of the patient's condition.

Fourth, through related auxiliary examinations, excluding physical illnesses that may cause symptoms of depression.

Ultimately, the diagnosis of depression is determined by integrating information from these four areas.