Bipolar disorder type II (BDII) has been considered since its
distinction from bipolar disorder type I (BDI) as a milder form, on the basis of cross-sectional symptoms intensity. Longitudinal data, on the contrary, do suggest that it is at least as severe as BDI, if not even more chronic and impairing. Few studies investigated differences in Axis II comorbidity in bipolar disorder patients according to bipolar subtypes, and none examined patients
during prolonged euthymia. The aim of the study was to determine comorbidity rates for personality disorders in euthymic bipolar subjects, comparing bipolar type I and II disorders (BDI and BDII). METHODS: 186 DSM-IV (SCID-I) bipolar disorder subjects were enrolled; all patients were euthymic for at least two
months, as confirmed by a HAM-D<8 and a YMRS<6. Axis II comorbidity was evaluated through SCID-II. Differences in Axis II comorbidity rates were examined with the Pearson's Chi-square test. RESULTS: Of the subjects included, 71 had BDI and 115 BDII. At least a personality disorder was present in 42.5% of all bipolars, 43.7% of BDI and 41.7% of BDII. No differences were detected between the two subgroups for any single personality disorder. LIMITATIONS: We relied only on the patients'
reports in assessing personality disorders; the sample was made of subjects referred to a tertiary centre who were able to maintain euthymia. CONCLUSIONS: Our study confirms the high comorbidity rates for personality disorders in
bipolar subjects and provides evidence that BDII, with regard to Axis II comorbidity, is as severe as BDI.
