Are the interpersonal and identity disturbances in the borderline personality disorder criteria linked to the traits of affective instability and impulsivity?

This study examines the degree to which two putative biologically influence d personality traits, affective instability and impulsive aggression, are a ssociated with some of the interpersonal and intrapsychic disturbances of b orderline personality disorder (BPD) and with choice of defense mechanism. In a sample of 152 personality disorder patients, affective instability and impulsive aggression were measured. Defense mechanisms were assessed in 14 0 of these patients using the Defensive Style Questionnaire (DSQ). The corr elations between the traits of affective instability and impulsive aggressi on and the eight DSM-III-R criteria for borderline personality disorder and 20 DSQ defenses were examined. Affective instability was significantly cor related with the DSM-III-R criteria of identity disturbance, chronic emptin ess or boredom, inappropriate anger, suicidality, and the affective instabi lity criteria. It also was associated with the defenses of splitting, proje ction, acting out, passive aggression, undoing, and autistic fantasy. Impul sive aggression was related to unstable interpersonal relationships, inappr opriate anger and impulsiveness and with the defense of acting out. It was negatively correlated with the defenses of suppression and reaction formati on. A number of the interpersonal and experiential disturbances and defense mechanisms that are features of BPD are associated with the traits of affe ctive instability and impulsive aggression among patients with personality disorders.