Clinical features
A factor analysis showed that aggression in bipolar
disorder was associated with paranoia and irritability
(Cassidy et al. 1998a). This irritable aggression
remained stable in time across consecutive manic
episodes (Cassidy et al. 2002).
In a more detailed study, aggression was associated
with irritability, uncooperativeness, impatience, and
lack of insight. Subsequent cluster analysis of this data
set revealed four subtypes of mania, one of them labeled
as “aggressive” (Sato et al. 2002). In a study of patients
with bipolar disorder, manic or mixed, aggression
appeared with similar frequency in the two subtypes
(Cassidy et al. 1998b).
Thus, aggression is a feature of manic and mixed
episodes of bipolar disorder, develops in the context of
irritability, and may be an enduring individual trait.
The preceding studies investigated symptoms
occurring contemporaneously with aggression. We will
now take a broader perspective, looking at concomitants
of aggression in bipolar disorder that are not necessarily
contemporaneous with aggressive behavior.