Borderline-Personality-Disorder (BPS), a severe psychiatric disorder, is characterized by a pervasive pattern of instability in affect regulation, impulse control, frequent experience of tension, self mutilating behavior, and multiple suicide attempts. About 70% of BPS patients show comorbidity with post-traumatic stress disorder (PTSD). In contrast to PTSD, there is a paucity of data on HPA and cardiovascular stress reactivity in BPS patients. One study showed increased cortisol awakening responses and higher daily cortisol levels in BPS patients compared to healthy controls. Therefore, we are currently investigating cortisol, heart rate, and blood pressure reactivity following a psychological challenge conducted during the first two weeks of an inpatient therapy program in 20 young women with BPS. All women are free of oral contraceptives and tested during the luteal phase. All tests are conducted in the afternoon. The psychological challenge is a 15-minutes lasting interview concerning the last suicide attempt or self injury focussing on cognitive and emotional aspects. As a control situation, a non-challenging interview was conducted. Since data collection is still in progress, results will be presented at the meeting.