Background: Despite numerous studies on the comorbidity of bipolar and anxiety disorders, there is no satisfactory psychopathological model for their overlap.
Method: 1,090 hospitalized patients meeting DSM-IV criteria for a manic episode of bipolar I disorder were subtyped according to the presence or not of lifetime anxiety comorbidity and assessed for demographic, illness course, clinical, associated condition, temperament, and treatment characteristics.
Results: Lifetime anxiety comorbidity, defined as presence of at least one anxiety disorder in lifetime, was found in 27.2% (n = 297) of the sample. Compared to patients without such a comorbidity (n = 793), those who had it experienced a higher number of mood episodes and suicide attempts in the previous year, more stressors, organic disorders and less free intervals; furthermore, they showed more temperaments with depressive features and complex treatment. At study entry, they also experienced manic episodes with higher levels of depression, psychosis and hostility. The following independent variables were associated with lifetime anxiety comorbidity: higher scores on the Montgomery-Asberg Depression Rating Scale, depressive temperament, irritable temperament, higher scores on the Scale for the Assessment of Positive Symptoms, episodes without free intervals and at least one stressor before the index episode.
Conclusions: Factors associated with lifetime anxiety comorbidity in bipolar I patients may be integrated into a comprehensive diathesis-stress model emphasizing the role of irritable temperament as a source of mood instability and stress, and interacting with other temperamental characteristics to trigger the outbreak of both anxiety and bipolar symptoms.
Copyright 2009 S. Karger AG, Basel.