Biological nature of depressive symptoms in borderline personality disorder: endocrine comparison to recurrent brief and major depression

Abstract

Borderline personality disorder (BPD) often shows depressive symptoms and their biological nature albeit extensively discussed remains controversial. The knowledge of this nature seems essential as it could imply key therapeutic strategies. We have found BPD and major depression (MD) not to share biological abnormalities. We have proposed BPD to frequently display an affective syndrome distinct from the nonborderline MD both in terms of quality and duration of symptoms and of biological substrate. A substantial number of BPD patients can be diagnosed as having clinical Recurrent Brief Depression (RBD) which has been proposed to overlap with BPD. RBD has been found to share perturbed biological substrate with MD but we have previously not found this abnormal substrate in BPD. Our aim was to study the possibility that BPD patients with depressive symptoms and even clinically diagnosed with RBD have a biological substrate distinct from RBD without BPD and from MD, and therefore an specific affective syndrome. We compared 20 BPD in-patients without co-existing MD to 20 sex- and age-matched non-BPD recurrent brief depressives and to 20 sex- and age-matched non-BPD major depressives on the thyrotropin-releasing hormone stimulation test (TRH-ST) and the dexamethasone suppression test (DST). Twelve BPD patients were diagnosed as having also RBD. BPD had less TRH-ST blunting than MD. TRH-ST did not differentiate BPD from RBD. RBD and MD patients shared equivalent TRH-ST values but BPD patients with clinically diagnosed RBD did not. BPD and RBD showed less perturbed DST than MD. DST did not differentiate BPD from RBD. BPD and RBD share most of the endocrinological normal substrate already described in BPD but RBD also share abnormalities with MD. Whereas we can conceptualize RBD as being an endocrinologically perturbed depressive syndrome, this may not be the case for the possible specific affective syndrome of BPD even if it can be for now diagnosed as being RBD.