IntroductionPsychosocial stress plays an important role in the development and manifestation of borderline personality disorder (BPD). Early life stress and traumatization are risk factors for BPD, and reports of traumatic childhood abuse are frequent in patients with BPD.1 Furthermore, patients with BPD ex peri ence psychosocial daily hassles more intensely than healthy individuals, indicating a reactivity and vulnerability to stress.2 Kuo and Linehan 3 measured higher skin conductance response in patients with BPD, which is positively correlated with stress. Moreover, the acute symptoms of patients with BPD are precipitated by acute stress. They show higher dissoci ative symptom scores than subjective stress ratings in comparison to healthy individuals and patients with major depressive and panic disorders. 4 Furthermore, high dissociation scores in patients with BPD correlate with greater childhood trauma and greater hypothalamus-pituitary-adrenal (HPA) axis reactivity to stress, 5 indicating a link between traumatic childhood experiences, endocrine stress response and acute symptoms. Under subjective stress, patients with BPD display a higher pain threshold, 6 and self-injurious behaviour is used as a means of stress reduction.7 It seems plausible that these stress-related symptoms may be linked to dysregulations in the functioning of the HPA axis, which is crucially involved in the body's response to stress. Correspondingly, patients with BPD show signs of abnormal cortisol reactivity and feedback regulation, indicating disturbed HPA axis functioning, although findings on baseline cortisol, HPA feedback sensitivity and cortisol responses to psychosocial stress in Background: Experiences of early life stress, increased psychological arousal and the body's physiologic stress response seem to play an important role in the pathogenesis and maintenance of borderline personality disorder (BPD). In the present study, we investigated alterations in grey matter of central stress-regulating structures in female patients with BPD. Methods: We examined T 1 -weighted structural magnetic resonance imaging scans of unmedicated, right-handed female patients with BPD (according to DSM-IV criteria) and healthy controls matched for age, intelligence and education using fully automated DARTEL voxel-based morphometry. Our regions of interest analyses included the hippocampus, amygdala, anterior cingulate cortex (ACC) and hypothalamus. Results: We enrolled 30 patients and 33 controls in our study. The grey matter of patients with BPD was reduced in the hippocampus, but increased in the hypothalamus compared with healthy participants. Hypothalamic volume correlated positively with the history of traumatization in patients with BPD. No significant alterations were found in the amygdala and ACC. Limitations: This study is limited by the lack of measures of corticotropin-releasing hormone, adrenocorticotropic hormone and cortisol levels. Furthermore, moderate sample size and comorbid disorders need to be considered. Conclusion: Our ...