Bipolar disorders (BDs) comprise different variants of chronic, comorbid, and disabling conditions, with relevant suicide and suicide attempt rates. The hypothesis that BD types I (BDI) and II (BDII) represent more and less severe forms of illness, respectively, has been increasingly questioned over recent years, justifying additional investigation to better characterize related sociodemographic and clinical profiles.

A sample of 217 outpatients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR)–described BD (141 BDI, 76 BDII), without a current syndromal mood episode, was recruited, and sociodemographic and clinical characteristics of BDI and II patients were compared.

BDII patients had significantly more favorable sociodemographics, in relation to occupational stability, cohabitation, and marital status. However, BDII compared with BDI patients had significantly longer duration of untreated illness, more frequent lifetime anxiety disorders comorbidity, longer most recent episode duration, higher rate of depressive first/most recent episode, and more current antidepressant use. In contrast, BDI compared with BDII patients had significantly more severe illness in terms of earlier age at onset; higher rate of elevated first/most recent episode, lifetime hospitalizations, and involuntary commitments; lower Global Assessment of Functioning score; and more current antipsychotic use. BDI and II patients had similar duration of illness, psychiatric family history, lifetime number of suicide attempts, current subthreshold symptoms, history of stressful life events, and overall psychiatric/medical comorbidity.

BDII compared with BDI patients had more favorable sociodemographic features, but a mixture of specific unfavorable illness characteristics, confirming that BDII is not just a milder form of BD and requires further investigation in the field.