To the Editor: We studied the relationship between acts of self-mutilation and fluctuations in levels of nocturnal urinary cortisol excretion in a female inpatient who developed borderline personality disorder after traumatization during childhood.
Ms. A, a 36-year-old woman, had pronounced repetitive self-mutilating behavior in addition to borderline personality disorder diagnosed according to an interview with the German version of the Dissociative Disorders Interview Schedule (1) (DSM-IV diagnoses 296.32, 300.6, 300.12, 300.15, 300.81, 301.83, and 307.1). She collected her entire nocturnal (8:00 p.m. to 8:00 a.m.) urine output on 86 consecutive nights (2) Her nocturnal urinary volumes were almost identical (mean=983 ml, SD=128), but the fluctuations in her nocturnal cortisol excretion were extreme, varying from 2 to 30 μg a night. Compared to normative data (cortisol excretion during 24 hours: 20–90 μg/day), her nocturnal cortisol secretion appears low on average; this is in accordance with data from other studies (3). However, our longitudinal study revealed that periods of low cortisol excretion were followed by periods of continuous increases in excretion over several nights. Above 20 μg a night, she performed one or several acts of self-mutilation. Subsequently, an instantaneous decrease to low initial baseline values of cortisol was observed. Thereafter, her nocturnal cortisol excretion remained at this low level for several days. The next period of increasing cortisol secretion was again terminated by an episode of self-mutilation.
It has long been speculated that self-mutilating behavior serves a coping function that is activated by an increase in emotional arousal (4, 5). Between 1 and 3 days before an episode of self-mutilating behavior, our patient reported increasing feelings of dissociation and depersonalization, flashbacks, and depressive states that were difficult to control either by herself or by therapeutic interventions. It seems that above a critical excitation threshold, Ms. A coped with escalating arousal with self-mutilating behavior.
We believe that our results provide the first empirical demonstration that episodes of self-mutilating behavior occur in response to hyperactivity of the central stress-sensitive neuroendocrine systems and increased cortisol secretion. Further longitudinal studies are needed to confirm this finding. Observations in nonhuman mammals have shown that self-mutilating behaviors may emerge as a consequence of deprived rearing conditions (6, 7). Thus, self-mutilating behavior may be regarded as an unusual but effective coping strategy for the self-regulation of hyperarousal and/or dissociative states and for regaining control over an otherwise uncontrollable stress response (8).