A factor analysis of the signs and symptoms of mania.

BACKGROUND

No adequate factor analyses of signs and symptoms of mania have been reported. From limited past reports, the view has arisen that 2 main symptom clusters (euphoric-grandiose and paranoid-destructive) occur in patients with mania, along with so-called core symptoms of psychomotor pressure. In this view, dysphoric mania is associated with paranoid-destructive symptoms and with psychosis.

METHODS

We rated 237 patients with DSM-III-R-defined bipolar disorder, manic (n = 204) or mixed (n = 33), on 15 classic features of mania and 5 features related to dysphoric mood. Principal components factor analysis was applied to the ratings.

RESULTS

Five clearly interpretable and clinically relevant factors were identified. The first and strongest factor represented dysphoria in mania, with strong positive loadings for depressed mood, lability, guilt, anxiety, and suicidal thoughts and behaviors and a strong negative loading for euphoric mood. Factors 2 through 5 represented psychomotor acceleration, psychosis, increased hedonic function, and irritable aggression, respectively. The distribution of weighted scores on factor 1 was bimodal, whereas the corresponding distributions of factors 2 through 5 were unimodal. Contrary to all past reports, no general factor denoting overall severity of mania was found. Factors previously proposed by Beigel and Murphy were not confirmed.

CONCLUSIONS

Five independent factors representing dysphoric mood, psychomotor pressure, psychosis, increased hedonic function, and irritable aggression were identified. The conventional view of symptom factors in mania was not confirmed. Dysphoric features are statistically salient in patients with mania, and the bimodal distribution of the dysphoria factor is consistent with the possibility that mixed bipolar disorder is a distinct state.