Syndromes and phenomenological subtypes underlying acute mania: a factor analytic study of 576 manic patients

There are no factor analytic studies specifically including symptoms representative of depressive inhibition among manic patients, although Kraepelin described several mixed affective states with depressive inhibition. There is controversy as to whether atypical manic features such as aggression, psychosis, and depression are likely to coexist among manic patients. The authors' goal was to examine this controversy.

They used a standardized instrument to assess the presence or absence of 37 psychiatric symptoms in 576 consecutive inpatients who were diagnosed as having DSM-IV manic episode, nonmixed or mixed.

A principal-component analysis followed by varimax rotation extracted seven independent interpretable factors (depressive mood, irritable aggression, insomnia, depressive inhibition, pure manic symptoms, emotional lability/agitation, and psychosis) that were relatively stable across several patient groups. A subsequent cluster analysis identified four phenomenological subtypes underlying acute mania: pure, aggressive, psychotic, and depressive (mixed) mania. Several variables, including gender, suicidality, and outcome of treatments, significantly differentiated the subtypes.

In patients with mania, depressive inhibition may be a salient syndrome independent of depressive mood, lending some support to Kraepelin's classification of mixed manic states on the basis of the permutations of three elements-thought disorder, mood, and psychomotor activity. Depressive inhibition, together with depressive mood and emotional lability/agitation, appears to be an important phenomenological element of mixed states. Atypical manic features such as aggression, psychosis, and depression are not likely to coexist, but they are likely separately to characterize several different subtypes potentially underlying acute mania.