Chronic depression subtypes: a 257 case study.

The aim of the study was to compare Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) three subtypes of chronic depression (chronic major depressive episode [MDE] occurring in major depressive and bipolar II disorders, dysthymic disorder with MDE, and MDE without full interepisode recovery occurring in major depressive and bipolar II disorders) with each other, and with nonchronic depression, and to find if this subdivision was supported by clinical data. Two hundred and fifty seven consecutive MDE outpatients were interviewed with the Structured Clinical Interview for DSM-IV, the Montgomery Asberg Depression Rating Scale (MADRS), and the Global Assessment of Functioning (GAF) scale. Clinical variables (age, age at onset, duration of illness, severity, gender, recurrences, atypical and psychotic features, axis I comorbidity, bipolar II, and unipolar diagnoses) were compared among the chronic depression subtypes, and versus nonchronic depression. Chronic MDE had significantly less comorbidity than the other two chronic depression subtypes. All the other variables were not significantly different. Chronic depression subtypes had significantly longer duration of illness, less comorbidity, and more recurrences than nonchronic depression. These findings do not support the DSM-IV subtyping of chronic depression.