Outlined in the preceding sections are what one could call the ABCDs of treating borderline patients. A = analytically informed psychotherapy; B = behavior therapy; C = cognitive therapy; and D = drug therapy. Together they add up to "E": eclectic therapy. In this pragmatic approach, the therapist will assess at the outset (1) amenability to exploratory therapy, but also (2) the need for supportive measures, including education, rehabilitation, and expansion of outside interests, (3) indications for behavioral technics (socially alienating habits, handwashing compulsions, phobias), (4) indications for cognitive measures (conflicts or fears resolvable through rational explanation or logical weighing of alternatives), and (5) indications for pharmacotherapy. All these steps involve the careful weighing of biologic/constitutional, psychodynamic, and, where present, posttraumatic factors, as well as personality assets and habitual problem-solving style. This will help assure against overreliance on a technic that does not fit with the patient's personality and against unwise persistence in a technic that is uncongenial or threatening. Patients already in stable life situations who are seeking help because of life crises may respond well to a brief course of therapy. Borderlines in late adolescence or early adult life, if self-destructive and not yet able to form lasting relationships (or to live contentedly without them), usually require sustained treatment over several years, preferably with the same therapist. Appropriate selection of medications, where indicated, should reduce impulsivity, aggressivity, and psychoticism. This, in turn, will facilitate psychotherapeutic work on maladaptive interpersonal patterns, exaggerated "all-or-none" responses to relatively innocuous stimuli, overpersonalized responses to other people's remarks, and so on. Therapists trained in identical methods will evaluate the same patient in somewhat different ways owing to their differences in personality and perception. This may lead to different sets of priorities and suggests different tactics that are still within the realm of therapeutic efficacy. Those trained primarily in one of the "ABCDs" may have equal success, yet via a different route than the one taken by therapists of a different subspecialty. Borderline patients, perhaps two out of five, often drop out of treatment no matter who the therapist. Yet two out of three patients, if followed long enough, eventually have a good result. One therapist's failure will be his colleague's success, and vice versa. Therapists, to maximize the success of their own efforts, need to be sufficiently steeped in at least one theoretical model of psychopathology/psychotherapy so as not to feel "lost" when confronted by the often bewildering dynamics and symptoms of their borderline patients.(ABSTRACT TRUNCATED AT 400 WORDS)