Non-Suicidal Self-injury is associated with Multidimensional Deficits in Interoception: Evidence from Three Studies

Non-suicidal self-injury (NSSI) is the deliberate and direct injury of one’s own body tissue without suicidal intent. As the known risk factors for NSSI predispose to a range of psychiatric disorders, there is a limited understanding of the specific individual differences that result in NSSI. Therefore, in three studies, a multidimensional approach examined the novel proposition that deficiencies in aspects of interoceptive processing represent one such individual difference. Study 1 and study 2 used principal component analysis to explore the underlying structure of the sub-scales from a variety of body awareness questionnaires. Three components emerged that were replicated across both studies; ‘interoceptive and emotional ambivalence’; ‘interoceptive awareness’; ‘interoceptive appreciation’. Study 3 extended the model examining the link between NSSI and the objective interoceptive index; ‘interoceptive accuracy’. Those with a history of NSSI were characterised by a difficulty in distinguishing and interpreting interoceptive signals and this effect was mediated by a low appreciation of these sensations. These effects were reliable across all three studies. In study 3, NSSI was also associated with lower interoceptive accuracy. These data suggest that a failure to accurately detect and conceptualise interoceptive signals may lead to a depreciation of the body, predisposing to NSSI. NSSI may serve to resolve the resulting state of emotional and interoceptive uncertainty associated with the body’s function in emotional experience. These findings offer new insight into the interoceptive processes that underlie NSSI and suggest specific pathways that could be addressed during clinical interventions.