The role of cyclothymia in atypical depression: toward a data-based reconceptualization of the borderline-bipolar II connection.

OBJECTIVE: Recent data, including our own, indicate significant overlap between atypical depression and bipolar II. Furthermore, the affective fluctuations of patients with these disorders are difficult to separate, on clinical grounds, from cyclothymic temperamental and borderline personality disorders. The present analyses are part of an ongoing Pisa-San Diego investigation to examine whether interpersonal sensitivity, mood reactivity and cyclothymic mood swings constitute a common diathesis underlying the atypical depression-bipolar II-borderline personality constructs.
METHOD: We examined in a semi-structured format 107 consecutive patients who met criteria for major depressive episode with DSM-IV atypical features. Patients were further evaluated on the basis of the Atypical Depression Diagnostic Scale (ADDS), the Hopkins Symptoms Check-list (HSCL-90), and the Hamilton Rating Scale for Depression (HRSD), coupled with its modified form for reverse vegetative features as well as Axis I and SCID-II evaluated Axis II comorbidity, and cyclothymic dispositions ('APA Review', American Psychiatric Press, Washington DC, 1992).
RESULTS: Seventy-eight percent of atypical depressives met criteria for bipolar spectrum-principally bipolar II-disorder. Forty-five patients who met the criteria for cyclothymic temperament, compared with the 62 who did not, were indistinguishable on demographic, familial and clinical features, but were significantly higher in lifetime comorbidity for panic disorder with agoraphobia, alcohol abuse, bulimia nervosa, as well as borderline and dependent personality disorders. Cyclothymic atypical depressives also scored higher on the ADDS items of maximum reactivity of mood, interpersonal sensitivity, functional impairment, avoidance of relationships, other rejection avoidance, and on the interpersonal sensitivity, phobic anxiety, paranoid ideation and psychoticism of the HSCL-90 factors. The total number of cyclothymic traits was significantly correlated with 'maximum' reactivity of mood and interpersonal sensitivity. A significant correlation was also found between interpersonal sensitivity and 'usual' and 'maximum' reactivity of mood. LIMITATION: Correlational study.
CONCLUSIONS: Mood lability and interpersonal sensitivity traits appear to be related by a cyclothymic temperamental diathesis which, in turn, appears to underlie the complex pattern of anxiety, mood and impulsive disorders which atypical depressive, bipolar II and borderline patients display clinically. We submit that conceptualizing these constructs as being related will make patients in this realm more accessible to pharmacological and psychological interventions geared to their common temperamental attributes. More generally, we submit that the construct of borderline personality disorder is better covered by more conventional diagnostic entities.