Subsyndromal symptomatic depression: a new concept.

Although DSM-IV acknowledged the clinical significance of some subthreshold forms of unipolar depression, such as minor depression (MinD) and recurrent brief depression (RBD), clinicians continued to struggle with the concept of "subthreshold" depression. A substantial number of patients continued to present with depressive symptoms that still did not satisfy any DSM-IV diagnosis. Generally, these patients failed to complain of anhedonia and depressed mood, a criterion that DSM-IV mandates for any diagnosis of depression. Therefore, researchers reexamined the question of whether this cluster of depressive symptoms, in the absence of anhedonia and depressed mood, was clinically significant. Some researchers labeled this cluster of symptoms, "subsyndromal symptomatic depression" (SSD). Specifically, SSD is defined as a depressive state having two or more symptoms of depression of the same quality as in major depression (MD), excluding depressed mood and anhedonia. The symptoms must be present for more than 2 weeks and be associated with social dysfunction. Using Medline Search, the authors reviewed the literature on the epidemiology, demographics, clinical characteristics, and psychosocial impairment of SSD. SSD is found to be comparable in demographics and clinical characteristics to MD, MinD, and dysthymia. SSD is also associated with significant psychosocial dysfunction as compared with healthy subjects. Further; it has significant risk for suicide and future MD. Few studies have been conducted on the treatment of SSD. The high prevalence of SSD, the significant psychosocial impairment associated with it, and the chronicity of its course make subsyndromal symptomatic depression a matter for serious consideration by clinicians and researchers.