Psychobiology of the borderline disorders--a heuristic approach.

A psychophysiologic approach to understanding borderline behavior is presented in which psychological and biological explanations complement, rather than exclude, one another. Descriptive-objective diagnoses or a target symptom approach are not sufficient to explain borderline behaviors. Phenomena are described that suggest underlying pathophysiologic processes, although they are usually accorded ego psychological explanations. Their underlying common denominator may be inadequate limbic system "filtering" of irrelevant stimuli. Each patient must be seen as an individual, rather than be fitted to a chosen model. Though the borderline constitutes a unique descriptive category, borderline behaviors result from processes generalizable across a broad range of psychopathology.