Depression is not a one-size-fits-all condition. Mental health professionals have long recognized that patients tend to display reasonably distinct clusters of clinical symptoms, and they increasingly regard such clusters as subtypes of depression.

The boundaries between subtypes are often fuzzy, with some overlap of symptoms, and not every depression expert agrees on the classification system. But clinical research suggests that parsing depression into subtypes is useful in guiding treatment and in gauging the long-term outcome for patients.

At a symposium presented at the recent meeting of the American Psychiatric Association, doctors discussed five depression subtypes that together encompass the majority of depressed persons. These include:

• Atypical depression, which studies show accounts for 23% to 36% of all cases and is under-recognized.
• Anxious depression, which afflicts 40% of patients with major depressive disorder and poses many treatment challenges.
• Melancholic depression, a severe form of disorder that is most common among persons hospitalized for depression.
• Vascular depression, a newly recognized variety that reflects the existence of silent cardiovascular disease and is most common among persons over the age of 60.
• Psychotic depression, a severe form of disorder distinguished by mood-congruent delusions and accompanied by specific changes in brain tissue.

The distinctions first emerged several decades ago on the basis of variations in response to then-available treatments. But clinicians and researchers suggest that dissecting depression into subtypes may be even more valuable today. The subtypes may represent distinct biological pathways of disorder and may ultimately provide clues to the multiple ways depression can arise as well as express itself.

Atypical depression can manifest in both bipolar and unipolar depression, psychiatrist Jonathan W. Stewart. M.D., of Columbia University reported. Patients with this variety of disorder — about 10 million Americans — have what physicians label mood reactivity: they can be cheered up at least 50% in response to positive events in their life, albeit temporarily.

In contrast to patients with classical depression, those with atypical depression overeat regularly and binge often, gaining sometimes substantial amounts of weight. They also sleep a lot, and experience a leaden paralysis and overwhelming fatigue for much of the day, feeling as if they cannot even lift themselves out of a chair.

In addition to such physical manifestations, atypical depression is marked by a longstanding pattern of extreme sensitivity to perceived interpersonal rejection that affects functioning at work, in love, and with friends. With a trail of stormy relationships patients are either never married or divorced, and are unemployed or underemployed. Given their fear of rejection, many withdraw from relationships entirely and refuse to go on job interviews.

    Last reviewed: By John M. Grohol, Psy.D. on 30 Jan 2013
    Published on PsychCentral.com. All rights reserved.