Restoring Melancholia as a Diagnostic Entity

The past one hundred years have seen a general broadening of the concept of depression (see Shorter, 2013). Once considered a serious mental disease seen in psychiatric inpatients, and rarely in outpatients, the concept of depression gradually expanded into a condition presently believed to afflict roughly 10 percent of the U.S. population (American Psychiatric Association, 2013).

Melancholia, by the Italian baroque painter Domenico Fetti (circa 1620).

Source: Public domain

The current iteration of DSM lists two main depressive illnesses: major depressive disorder (MDD) and persistent depressive disorder (PDD), also known as dysthymia. The classic psychiatric term for depression, melancholia, is found only as a specifier for MDD and bipolar disorder, i.e., with melancholic features, though it shares only some commonalities with the original concept of melancholia (Parker et al., 2013). Melancholia is not currently a standalone psychiatric diagnosis.

An article published in the Journal of Affective Disorders in 2008 by Michael Alan Taylor and Max Fink argues that melancholia should be restored to the psychiatric nomenclature as a disorder of its own. The authors write, "Melancholia... is a disorder with definable clinical signs that can be verified by laboratory tests and treatment response. It identifies more specific populations than the present system and deserves individual identification in psychiatric classification. Its re-introduction will refine diagnosis, prognosis, treatment selection, and studies of pathophysiology of a large segment of the psychiatrically ill" (Taylor & Fink, 2008, p. 1).

The concept of melancholia refers to a severe, lifetime, and biologically-based depression that is characteristically unresponsive to psychotherapy. Its clinical features include disturbances in affect, psychomotor disturbance, cognitive impairment, vegetative dysfunction, and, often, psychosis (Parker et al., 2013). It has been variously described as "melancholic," "endogenous" (owing to its biological cause), "autonomous," "psychotic," and "typical" depression.

Patients presenting with this classic psychiatric syndrome often also fail to respond to traditional antidepressant therapy and may require treatment with electroconvulsive therapy, transcranial magnetic stimulation, or lithium augmentation. The dexamethasone suppression test, one of the few biological tests in psychiatry, has been shown to aid the diagnosis of melancholia (Parker et al., 2013). Roughly 60 percent of patients referred for electroconvulsive therapy have a melancholic depression (Kaplan, 2010). The recent introduction of ketamine therapy to psychiatry may also prove to be a successful strategy in treating these patients.

The inclusion of a separate entity of melancholia to future versions of DSM would serve the important purpose of identifying a subset of depressed patients who may respond to these particular treatments. It also distinguishes the seriously ill from those with mild or moderate variants of depression. Under the current diagnostic system, all of these patients are diagnosed as having the same disorder: major depressive disorder. As Taylor & Fink (2008) argue, there is good reason to suspect that melancholia reflects a disease that is unique and distinct from milder, transient, situational, or exogenous depressions.

A second related consequence of reintroducing melancholia as a diagnostic entity would be the refinement of treatment selection for depressed patients. An abundance of research indicates that psychotherapy is the treatment of choice for those with mild to moderate depression (see, for example, Bortolotti, Menchetti, Bellini, Montaguti, & Berardi, 2008), though, in practice, antidepressants are all-too-frequently used in these cases, particularly by primary care physicians and other non-psychiatrists.

By distinguishing melancholia from relatively milder forms of depression, providers would be more likely to tailor depression treatment to the severity of the disease. In practice, this would mean that patients with milder, exogenous depressions are treated appropriately with psychotherapy and those with melancholia are treated via biological means.

Future versions of the DSM system should include a separate diagnosis reflecting the unique entity of melancholia. Psychiatry should return to its roots in this regard and officially recognize a disease readily identified since the birth of modern medicine.