Emotion in Non-Suicidal Self-Injury

People who engage in non-suicidal self-injury (NSSI) report doing so largely to

manage overwhelming emotions. Prominent theories of NSSI argue that an amplified

emotional response system creates the context in which a person chooses to regulate their

emotions by engaging in NSSI. In line with these theories, people who engage in NSSI

consistently report greater global emotion reactivity and emotion dysregulation than do

controls. These global self-reports of emotional functioning also predict the onset and

cessation of NSSI, demonstrating their considerable utility in understanding the behaviour.

However, global self-reports provide an overall evaluation of one's average affective

experience and so are ill-suited to isolating precise alterations in emotional responding.

I first establish how best to assess NSSI (Study 1a and 1b). I then leverage

experimental affective science and individual differences methodologies to test whether NSSI

is characterised by a more reactive and intense emotional response to challenge, and/or

whether factors that help to create, modify, and later recall the emotional response are altered

in those who engage in NSSI compared with controls. Study 2 compared how young adults

with a past-year history of NSSI and controls subjectively and physiologically reacted to, and

recovered from, acute stress. Study 3 compared how young adults with a past-year history of

NSSI and controls subjectively reacted to both explicit and more ambiguous social exclusion.