According to a 1999 article published by McLean Hospital, "DBT is based on a biosocial theory of personality functioning in which BPD is seen as a biological disorder of emotional regulation. The disorder is characterized by heightened sensitivity to emotion, increased emotional in-tensity [sic] and a slow return to emotional baseline. Characteristic behaviors and emotional experiences associated with BPD theoretically result from the expression of this biological dysfunction in a social environment experienced as invalidating by the borderline patient."[5]