Subsyndromal Symptomatic Depression

Summary

There is very strong evidence in the literature indicating that the presence of subthreshold depressive symptoms is not a benign clinical condition. At least 5 separate investigational groups, including our own, have confirmed that the presence of depressive symptomology not reaching the diagnostic threshold for a DSM-III-R mood disorder diagnosis is correlated with social dysfunction, work impairment and absenteeism, and the potential risk of future episodes of major depression.

We have labelled this condition ‘subsyndromal symptomatic depression (SSD)’. A secondary analysis of the National Institute of Mental Health Epidemiological Catchment Area (ECA) Programme database has demonstrated that SSD has a 1-year prevalence of approximately 8% in the general population. The majority of those with SSD were female (approximately 63%) and they presented with a clinical symptom picture that closely resembled that of major depression. However, it was notable that the feature of 14 days of dysphoria/anhedonia, which is a required criterion for a mood disorder diagnosis in the DSM-III-R system, was absent from these patients. It was also noted that patients with SSD more frequently received social welfare and disability benefits than did the general population without depressive symptoms.

We have concluded that SSD does represent a significant clinical problem that is not covered by any DSM-III, DSM-III-R or DSM-IV mood disorder diagnosis. Furthermore, this disorder is of considerable importance in public health. An ongoing clinical trial is investigating the efficacy of fluoxetine in SSD.