We have defined melancholia as a depressive mood disorder characterized by psychomotor retardation and agitation, disturbances in vegetative functions, loss of interest, impaired concentration and memory, delusional thoughts, and preoccupation with suicide. Psychotic depression, depression that is part of a manic-depressive course, depression with catatonia, puerperal depression, and abnormal bereavement are melancholic illnesses. The evidence for including these conditions as melancholic disorders is discussed in Chapter 2.

Many other depressive disorders are delineated in psychiatric classifications that may or may not meet the criteria for melancholia. Atypical depression, dysthymia, seasonal affective disorder (SAD), adjustment disorder with depression, and similar syndromes are poorly defined. They encompass heterogeneous samples of patients who are best considered as having a non-melancholic mood disorder (Table 6.1).

Non-melancholic depressive mood disorders

Non-melancholic “major depression”

Cluster and latent class analyses identify depressed patients who do not exhibit melancholic features (Table 6.2). The studies do not indicate whether this group can be divided further.