Depressive personality and dysthymia: evaluating symptom and syndrome overlap.

BACKGROUND: Depressive Personality (DP) is being evaluated for future inclusion in DSM. One recurring issue has been conceptual and empirical redundancy with Dysthymia (i.e., Dysthymic Disorder; DD).

METHODS: The symptom and syndrome overlap of DP and DD were tested in a clinical sample (N = 125) using both self-report and clinician ratings.

RESULTS: Confirmatory factor analyses of the DP and DD symptoms indicated that models which separate these two syndromes had a better fit than a model in which all symptoms were classified together, particularly for the clinician-rated data. At the same time, the syndromes were highly correlated. Binary diagnostic analysis showed that over 80% of the individuals meeting criteria for DP also met criteria for DD. As predicted, the best fit was obtained when the 'psychological' symptoms of DD-- low self-esteem and feelings of hopelessness-- were allowed to be part of both syndromes, and 82% of patients who met criteria for both DP and DD endorsed these two symptoms.

LIMITATIONS: Clinical ratings rather than structured diagnostic interviews were used. As well, some models required modification to improve fit.

CONCLUSIONS: Depressive personality traits can be empirically separated from DD symptoms, but including DP as a categorical diagnosis would lead to a high degree of diagnostic overlap. Much of this overlap is due to sharing psychological features in common. Revisions in the diagnostic system should find a way to incorporate depressive personality traits without insisting that they be diagnosed in a categorical manner.