Both preclinical studies25 and clinical studies suggest that a more fine-grained multidimensional approach to impulsivity may be warranted and that nonplanning impulsivity may be a key ingredient of BPD. Aggression One of the more common impulsive behaviors evidenced by people with BPD are expressions of anger or reactive aggression. Thus, the kind of anger that is observed in BPD Inhibitors,research,lifescience,medical patients is an impulsive type of aggression, but the aggressive components may be analyzed by somewhat different measures than the impulsive components. For example, psychometric measures designed to measure aggression include the Buss-Perry Aggression Questionnaire (BPAQ),26 as well as measures

of life history of overt aggressive behaviors (life history of aggression [LHA]). Both measures have well-established psychometric properties and heritability has been established in twin studies using the Buss Durkee Hostility Interview (BDHI),27 a precursor of the BPAQ. Preliminary data also suggest that life history of aggression may be heritable. Laboratory Inhibitors,research,lifescience,medical paradigms that assess aggression behaviorally are available, including the Point Subtraction Aggression Paradigm (PSAP).28 In the PSAP, an experimental subject is instructed to accumulate “points” that can be exchanged for money and is told that they are playing in conjunction with a “confederate subject,” while in reality responses are generated by Inhibitors,research,lifescience,medical computer. Aggressive

responses are often retaliatory to provocations from the “confederate” and do not net the subject of the study HCS assay actual “points,” but may be initiated as an aggressive response to the perceived aggression of the confederate. Inhibitors,research,lifescience,medical The PSAP has been externally validated in violent and nonviolent male parolees and responses to this laboratory test have been correlated with other psychometric measures of aggression.29 The heritability of this laboratory measure has not been definitively established, but is being systematically assessed

in studies of twins Inhibitors,research,lifescience,medical (Coccaro et al, personal communication). Another laboratory test for evaluating the propensity for aggression in response to provocation is the Taylor Aggression Paradigm,30 in which aggressive responses to mild electric shocks are administered to the subject, ostensibly by a fictitious opponent. Aggressive behavior is evaluated as a function of the shock intensities administered by the subject Nature Reviews Cancer to this fictitious opponent. This paradigm has been used extensively in the evaluation of alcoholinduced aggression31 and has been applied to studies of reactive aggression in BPD (Coccaro et al, personal communication). Aggressive responding in the PSAP paradigm is a stable trait that can distinguish between aggressive and nonaggressive subjects, but, for both of these measures, the precise prevalence in specific personality disorders, such as BPD, and the degree of genetic influence on the PSAP has not been determined.