The authors review the available literature on the interface between
borderline personality disorder and affective disorder. Three competing
hypotheses have been offered to explain the substantial overlap between
these diagnostic categories; they postulate that borderline disorder arises
from affective disorder, that affective disorder arises from borderline
disorder, or that the two are independent and overlap coincidentally. None
of these hypotheses satisfactorily explains the existing data. The authors
propose a fourth hypothesis focusing on the multiple etiologies of the
signs and symptoms used to diagnose both affective and borderline disorders
and suggesting that some patients in the resulting heterogeneous population
have symptom clusters that fit both syndromes.Abstract Teaser