Borderline Personality Disorder

IN 1682 the English physician Thomas Sydenham captured the essence of borderline personality in a single phrase. "All is caprice," he wrote, "they love without measure those whom they will soon hate without reason." 1 Three centuries later, this remains the most succinct diagnostic statement ever made about one type of pathologically dependent patient. Then called "hystericks," today's "borderlines" are still known by their impulsivity, drastic swings from love to hate, and irrationality bordering on madness.2 3 4 5 Sydenham's tone shows another sign, the physician's troubled reaction to such patients.6 Borderlines are extremists who split the world into exaggerated dichotomies of good and . . .