Objective: To examine whether minor depression differs from major depression in clinically relevant ways.
Method: Structured interviews, Symptom Checklist-90-Revised (SCL-90-R) scores, and physicians' treatment recommendations were obtained systematically from 1,458 admissions to an outpatient teaching clinic during a 5-year period from 1981 to 1986. Of these, 1,002 (69%) satisfied inclusive DSM-III lifetime criteria for a major depressive episode. Of the 456 outpatients who did not formally satisfy criteria for a major depressive episode, 79 (17%) acknowledged significant depressive symptoms that caused major interference in their lives. These 79 outpatients were classified as suffering from minor depression.
Results: No gender or other sociodemographic differences were found between the 2 outpatient groups except that the minor depression group had achieved a higher level of education. No differences were found for a family history of psychiatric illness among first-degree relatives, including a family history of depression. Ratings of childhood unhappiness/problems did not distinguish the 2 groups. The major depression group endorsed more lifetime depressive symptoms and met criteria for more co-occurring disorders, principally mania and the anxiety disorders. The group with major depression reported poorer psychosocial functioning when first seen and more past psychiatric treatment. The Symptom Checklist-90-Revised (SCL-90-R) profile was significantly elevated in both groups. The type of initial treatment recommended did not distinguish the major from minor depression groups.
Conclusions: Minor depression seems to represent the same illness as major depression but in a less severe form that, nevertheless, requires the attention of professional health care providers in both primary and specialized care settings.