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.