Kaysen, borrowing from the Diagnostic and Statistical Manual of Mental Disorders, clinically describes the presentation of Borderline Personality Disorder, her diagnosis upon entering McLean. The disease creates a “pervasive pattern of instability of self-image, interpersonal relationships, and mood.” Self-image, sexual orientation, long-term goals, and values are all rendered unstable by this “marked and persistent identity disturbance,” and the instability spreads to mood and behavior. Shopping sprees, substance abuse, recklessness, casual sex, binge eating, suicidal threats, self-mutilating behavior, social contrariness, and recurrent physical fights are just a few “presentations” of BPD. The disorder is more frequently diagnosed in women, and complications of BPD include neurosis, major depression, substance abuse, psychosis, and premature death from suicide. According to the DSM, no information on social or genetic predisposition to the disease is available.
As Susanna Kaysen outlines in clinical terms the definition, patterns, and presentations of the “character disorder” which derailed her adolescence and came to define much of her adult life, the blurry boundaries of the disorder become apparent. Reckless behavior, instability, uncertainty, and “contrariness” are behaviors which many experience over the course of a lifetime. Though a BPD diagnosis technically necessitates demonstration of a “pervasive pattern” of engagement in these behaviors, it is impossible to say conclusively whether Susanna Kaysen herself could have truly or rightly been categorized, at just eighteen, as a sufferer of BPD.