Increasing incidence rates of self-harm has become a growing clinical problem with it being estimated that 4 in every 1,000 people within the UK engage in self-injurious behaviours (Mental Health Foundation, 2019).

Emotion regulation is suggested to be an explanation as to why individuals self-harm, however, we are yet to identify how a painful stimulus such as self-harm improves affect. Causal factors need to be understood in greater depth to improve treatment outcomes.

Interoception refers to the physiological state of the body and one’s sense of internal bodily signals. Self-harm compensates for difficulties in predicting and understanding these bodily signals associated with emotion. Linked to autonomic changes accompanying emotion are expectations about their sensory consequences. When sensation is unpredictable a mismatch between perceived and actual bodily changes, negative affect and a continuing sense of dysregulation results. Data suggests that self-harm reduces unwanted emotions because the sensory consequences of self-harm are expected (Young et al., 2019).

This project aims to answer:

• Do those who engage in self-harm feel emotions in their body more?
• Do individuals use self-harm to feel their emotions physically?
• How does a painful stimulus such as self-harm improve affect?

The most effective existing interventions are extensive and help individuals manage and label emotions. However, a significant obstacle is that there is no effective way to make sensations predictable, and therefore alter emotional state. Working alongside collaborative partners, Dechrau Newydd (Swansea Bay University Health Board), this research will develop and test a novel treatment paradigm to increase interoceptive certainty in individuals with Borderline Personality Disorder (BPD) and consequently managing self-injurious behaviours.

It is anticipated that the research outcomes will have an impact within the field of clinical psychology, to be used in practice to improve the lives and manage self-injury in individuals with BPD and form the basis of future interoceptive treatments.