Dexamethasone suppression test in borderline personality disorder--effects of posttraumatic stress disorder

Divergent findings of hypothalamic-pituitary-adrenal (HPA) axis functioning in borderline personality disorder (BPD) may be caused by a different degree of comorbid posttraumatic stress disorder (PTSD), in which alterations of the HPA axis are well known. Here we investigate alterations of the HPA axis in BPD patients with and without comorbid PTSD compared to healthy controls. Considering previous findings current major depression (MDD) was taken into account as a confounding variable.

Apart from clinical assessment the 0.5 mg dexamethasone suppression test (DST) was performed in 21 female borderline patients and 23 healthy controls.

Twelve BPD patients suffered from comorbid PTSD. Relative suppression (%) did not differ between healthy controls and the total BPD group, but BPD patients with comorbid PTSD showed increased suppression compared to those without. Comorbid MDD was not associated with suppression.

Our results do not indicate a dysfunction of the HPA axis in BPD. However, comorbid PTSD seems to be associated with a relative hypersuppression in the 0.5 mg DST.