A Bidimensional Solution for Outcomes in Bipolar Disorder

Although depressive symptoms have been consistently associated with lower quality of life and increased disability in bipolar disorder, their relation to manic symptoms is not as clear cut. A great overlap between these outcomes complicates the understanding of how they cluster together. We used exploratory factor analysis to clarify the relation between these constructs. We consecutively recruited 320 patients with bipolar disorder, and interviewers rated the Hamilton Depression and Anxiety Rating Scales, the Young Mania Rating Scale (YMRS), Clinical Global Impression (CGI), and the Global Assessment of Functioning (GAF). The self-rated Sheehan Disability Scale and the World Health Organization Quality of Life-BREF questionnaires were also collected. Two distinct and large dimensions emerged. Depression and anxiety, along with the self-rated scales, loaded in the first factor, whereas the YMRS, the GAF, and the CGI loaded in the second. These findings imply that evaluating self- and observer-rated outcomes may make up for a more thorough evaluation because each conveys unique illness information.