The main objective of this study was to determine whether being taught the latest information concerning borderline personality disorder (BPD) leads to a decline in core BPD symptoms and an improvement in psychosocial functioning. Fifty-five late adolescent women participated in a rigorous diagnostic assessment and 50 met DIB-R and DSM-IV criteria for BPD. All 50 were informed that they met criteria for BPD. Then 30 were randomized to a psychoeducation workshop that took place within a week of diagnostic disclosure. The other 20 were assigned to a waitlist and participated in the workshop at the end of this 12-week study. The two primary outcome measures were readministered each week of the trial: the Zanarini Rating Scale for DSM-IV Borderline Personality Disorder (ZAN-BPD) and the Sheehan Disability Scale (SDS). Immediate psychoeducation concerning the BPD diagnosis was associated with a significantly greater decline in general impulsivity and the storminess of close relationships. However, it did not result in significantly improved psychosocial functioning. Taken together, the results of this study suggest that informing patients about BPD soon after diagnostic disclosure may help to alleviate the severity of two of the core elements of borderline psychopathology-general impulsivity and unstable relationships. They also suggest that such instruction may prove to be a useful and cost-efficient form of pre-treatment.