Endophenotypes in BPD BPD has been formulated as an emergent personality disorder grounded in the interaction of underlying genetically based dimensions including impulsive aggression, affective instability, and altered emotional information processing. Identifying endophenotypes for these partially discriminable dimensions may thus represent a more achievable goal than identifying endophenotypes for the more complex parent disorder. For each dimension, diagnostic interview criteria, psychometric variables from self-report measures, laboratory behavioral tests, neurochemical variables and neuroimaging paradigms, postmortem neurochemistry and molecular

biology techniques, Inhibitors,research,lifescience,medical as well as brain structural techniques, also represent potential endophenotypes that may identify promising genotypes (Figure Inhibitors,research,lifescience,medical 1 and

2). Figure 1. Identifying promising genotypes from a diagnostic category. Figure 2. Identifying promising genotypes in borderline personality disorder. PSAP, Point Subtraction Aggression Paradigm; CPT, Continuous Performance Inhibitors,research,lifescience,medical Task; IMT, Immediate Memory Task; fMRI, functional magnetic resonance imaging; PET, phosphatase inhibitor library positron emission tomography; … Impulsivity Impulsivity is a central characteristic of many of the cluster B personality disorders and, as noted above, most aggressive acts committed by personality-disordered patients represent impulsive rather than planned aggression. Impulsive aggression may also be directed toward the subject himself or herself as in self -injurious behavior. Other forms of impulsive behavior, such as binge eating, reckless driving, or gambling, may also be observed in personality-disordered patients. Impulsivity is thus defined as a propensity or readiness to act without reflection or appropriate Inhibitors,research,lifescience,medical constraint, Inhibitors,research,lifescience,medical often resulting in behaviors that bring on negative consequences such as aggression; it is a critical

dimension of BPD12 and, as discussed above, appears to be heritable, relatively stable in longitudinal studies, and a potential target for both pharmacological and psychosocial treatment. While impulsivity is often expressed in the domain of aggression in BPD, the two dimensions may be partially discriminable and will be treated separately. Psychometric measures that might be used for assessments of impulsive tendencies include the Barrett Impulsivity Scale (BIS-11)22,23 and interviews that evaluate life history of actual impulsive behaviors, such the as the Life History of Impulsive Behavior.24 These psychometric measures may be complemented by laboratory assessments that identify critical components of impulsivity. For example, the Immediate Memory Task (IMT) reflects “attentional impulsivity,” while go/stop tasks or go/no go Continuous Performance Tasks (CPTs) reflect a disinhibition or “motor impulsivity.” The Single Key Impulsivity Paradigm (SKIP) reflects “nonplanning impulsivity.