Dimensions of self-rated mood in depressed, manic, and normal subjects.
Self-rated scales allow the comparison of subjective mood across the spectrum of manic, depressive, and euthymic states. This study examined the self-reported mood of manic, depressed, and normal subjects using a 23-item research instrument based on the Carroll-Klein model of bipolar disorder. The Multiple Visual Analog Scale (MVAS) measures the following dimensions: consummatory reward (seven items), incentive reward (two items), psychomotor speed (seven items), and central pain (seven items). The MVAS was completed by 31 manic inpatients, 43 depressed inpatients, and 29 normal volunteer subjects. Total scores, average item scores, and total dimension scores were obtained. Subjects also completed a global mood VAS and the Carroll Depression Scale (CDS). Groups were compared by analysis of variance (ANOVA) and post hoc Bonferroni-Dunn methods. In a separate post hoc analysis, the group of manic patients was divided at the median CDS score into "pure" and "dysphoric" manic subgroups. We found excellent congruence of average 23-item total MVAS scores with global VAS and CDS scores. Dimension scores on the MVAS conformed to the predictions of the Carroll-Klein model. Depressed patients differed significantly from both manic and normal subjects on each dimension. MVAS dimension scores of normal subjects did not differ significantly from those of manic patients. On the dimension of central pain, normal subjects had significantly less inhibited scores than the "pure" subgroup of manics. The results confirmed that the dimensions of the Carroll-Klein model are bipolar and orthogonal. By the MVAS technique, the self-reported mood of normal subjects is similar to the self-reported mood of manic patients on all dimensions of the Carroll-Klein model of bipolar disorder. The positive scores of both groups are clearly distinguished from the negative scores of depressed patients. Average MVAS scores of normal subjects approximated the conventional zero score only on the dimension of central pain. Normal subjects exhibit megalothymic (hyperthymia) on most dimensions of subjective mood. The negative MVAS scores of depressed patients are even more deviant from normal than the conventional scoring system would suggest.