Introduction: Several lines of evidence have well established a relationship between Bipolar Disorder and Cluster B Personality Disorders. The study compares mood spectrum and temperamental symptoms, personality traits and clinical characteristics among outpatients (n = 63) diagnosed with major depression (MD), bipolar disorder (BD), cluster B personality disorders (PD-B) and comorbidity of BD + PD-B.
Method: The diagnosis was determined with structured interviews (MINI and SCID II) and symptom assessments with evaluation and diagnostic instruments (MOODS-SR, BI, TEMPS-A and IPDE). Differences between groups were explored with post hoc analysis and analysis of variance.
Results: Patients with BD+PD-B comorbidity presented an earlier onset and more severity in suicide attempts, hospitalizations and self-harm behaviors. They showed more characteristics of cyclothymic and irritable temperament and more cluster A and B personality traits, than patients with BD only. PD-B patients obtained intermediate scores in manic like symptoms: higher than patients with depression and lower than patients with bipolar disorder. However, the Bipolarity Index clearly distinguished patients with BD or with comorbidity (BD+PD-B) from the other diagnostic groups (PD-B and MD).
Conclusions: BD+PD-B comorbidity presents a more severe type of emotional dysregulation compared to the other diagnostic groups, including BD and PD-B alone. Assessing temperament, personality traits, emotional dysregulation in mania and depression, self-harm and hospitalizations severity and age onset could facilitate differential diagnosis and enhance effectiveness of treatments for BD, PD-B and their comorbidity.