Johnson SL, Morriss R, Scott J, Paykel E, Kinderman P, Kolamunnage-Dona R, Bentall RP. Depressive and manic symptoms are not opposite poles in bipolar disorder.
Objective: This study of 236 individuals with bipolar disorders employed longitudinal analyses to determine whether the symptoms of mania and depression can be understood as one dimension (with depression and mania as opposites) or two relatively independent dimensions.
Method: Weekly severity ratings of manic and depression were assessed using the Longitudinal Interval Follow-up Evaluation-II for 72 weeks. The within-subjects correlation of manic and depressive severity was examined using random effects regression.
Results: Contrary to the one-dimension model, mania and depression symptoms were not negatively related. Indeed, the correlations of mania with depressive symptoms were quite small.
Conclusion: The data suggest that depressive and manic symptoms are not opposite poles. Rather depressive and manic symptoms appear to fluctuate relatively independently within bipolar disorder.