Diagnosing major depressive disorder V - Applying the DSM-IV exclusion criteria in clinical practice

To be diagnosed with DSM-IV major depressive disorder (MDD), a patient must meet five out of nine symptom criteria, one of which is depressed mood or pervasive loss of interest or pleasure. Once a patient has reached this symptom threshold, there are several exclusionary criteria that need to be passed to receive the diagnosis. The symptoms must cause significant distress or impairment in functioning, the symptoms cannot be caused by substance use or a general medical condition, and the symptoms cannot be better accounted for by bereavement. Finally, the presence of psychotic symptoms not coincident with the depressive symptoms excludes the diagnosis. We are not aware of any studies of psychiatric patients that have examined the impact of all of these exclusionary rules on the diagnosis of MDD in clinical practice. It is important for clinicians to know how often each of these factors might exclude the diagnosis of MDD so that they can be more or less vigilant to their presence. The goal of the present report from the Rhode Island Methods to Improve Diagnostic Assessment and Services project was to examine the impact of the DSM-IV exclusion rules on the diagnosis of MDD, In total, 38 (3.0%) of the 947 patients meeting the DSM-IV symptom inclusion criteria were excluded from a diagnosis of MDD or bipolar depression. These results suggest that the DSM-IV exclusion criteria for MDD had only a modest impact on diagnosis in psychiatric outpatients. It is likely that the results of a study of the impact of the DSM-IV depression exclusion criteria will depend on where the study is conducted. The potential influence of different settings on diagnostic exclusion is discussed.