Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)




Non-suicidal self-injury (NSI) represents a growing area of concern in a variety of clinical settings, yet remains a poorly understood phenomenon. An influx of research on the functions of NSI over the past decade has suggested a biopsychosocial emotional regulation model of this behavior. This model proposes that self-injurers engage in NSI to reduce negative emotions, and presupposes that self-injurers are characterized by emotional dysregulation. The present study evaluated the biological component of this model by assessing hypothalamic-pituitary-adrenocortical axis (HPAA) functioning in a group of self-injurers(n=26) and non-injuring healthy controls (n=28). HPAA functioning was assessed via measuring salivary cortisol levels across 65 minutes following exposure toan interpersonal rejection stressor or neutral comparison condition. Results of the experiment did not support the biological facet of the proposed biopsychosocial model. A complex time x condition x group x gender interaction effect was found, which was counterintuitive to study hypotheses. However, self-reported difficulties with emotional regulation were in the hypothesized direction, with self-injurers reporting greater difficulties in most domains. Future research must seek other potential lines of evidence in support of the biological aspects of emotional regulation in self-injurers.

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