Changes in energy and motor activity: core symptoms of bipolar mania and depression?

Objective: To evaluate how well symptom rating scales differentiate bipolar disorder (BD) episode types. Methods: One hundred and six patients with BD were followed for 13 years. At each visit, the following clinical scales were administered: Young Mania Rating Scale (YMRS), Hamilton Depression Scale (HAM-D) and Clinical Global Impressions scale for use in bipolar illness (CGI-BP). To perform a comparison between the affective states of BP, three time points in each patient's follow-up period were chosen for evaluation: the most severe manic episode, the most severe depressive episode, and the euthymic period with least symptoms. Canonical discriminant analyses (CDA) were performed to identify which symptoms best discriminated episodes. Results: CDA revealed HAM-D was worse than YMRS and CGI-BP to discriminate mood states. The items evaluating increased motor activity in YMRS (2, increased motor activity/energy) and HAM-D (9, agitation) were the best to distinguish mania, depression, and euthymia. In contrast, HAM-D item 8 (retardation) and the HAM-D and YMRS items related to mood symptoms were less important and precise. Conclusion: Higher levels of energy or activity should be considered a core symptom of mania. However, our results do not confirm the association between a decrease in energy or activity and depression. HAM-D probably does not assess motor activity adequately.