Anxiety comorbidity in bipolar spectrum disorders: the mediational role of perfectionism in prospective depressive symptoms.

BACKGROUND: Bipolar spectrum disorders (BSDs) are highly comorbid with anxiety, which is associated with an extended duration and exacerbation of depressive symptoms. Unfortunately, the underlying mechanisms are not known. This study examined the role of maladaptive cognitive styles in the co-occurrence of BSDs and anxiety disorders and prediction of depressive symptoms.
METHODS: Participants included 141 young adults (69.6% female, mean age=20.24, SD=2.11), in one of three groups: a BSD group (bipolar II, cyclothymia, n=48), a comorbid BSD/anxiety group (n=50), and a demographically-matched healthy control group (n=43), who were followed prospectively. Participants completed the Cognitive Style Questionnaire (CSQ), Depressive Experiences Questionnaire (DEQ), Dysfunctional Attitudes Scale (DAS), Sociotropy Autonomy Scale (SAS), Halberstadt Mania Inventory (HMI) and Beck Depression Inventory (BDI) at the initial assessment. One year later, participants completed the BDI and HMI again to assess severity of depressive and hypomanic/manic symptoms.
RESULTS: A multivariate analysis of co-variance (MANCOVA) revealed significant differences between the three groups on their DAS Perfectionism, DEQ Dependency, DEQ Self-Criticism, CSQ Negative, SAS Autonomy, and Time 2 BDI scores, with the BSD/anxiety group scoring higher than the BSD only group on all measures except the CSQ. Preacher and Hayes׳ (2008) bootstrapping method was used to test for mediational effects of the significant cognitive style measures on depressive symptoms at follow-up. The 95% confidence intervals for the indirect effect of group on follow-up depressive symptoms through DAS Perfectionism did not include zero, indicating the presence of a significant mediating relationship for perfectionism. LIMITATIONS: This study only used two waves of data; three waves of data would allow one to investigate the full causal effect of one variable on another. Further, a comorbid anxiety diagnosis consisted of any anxiety disorder. Further research should separate groups by their specific anxiety diagnoses; this could afford a more complete understanding of the effect of types of anxiety on prospective depressive symptoms.
CONCLUSIONS: After taking into account initial levels of depressive and hypomanic/manic symptoms, we found that those with BSD/anxiety comorbidity experienced more severe depressive symptoms, but not more severe hypomanic/manic symptoms. Further, their more severe prospective depressive symptoms are explained by a perfectionistic cognitive style.