Emotion processing and electrodermal activity in young people who self-harm

The biological underpinnings of self-harm in young people are unclear. Self-harm often serves to regulate emotions, and electrodermal activity (EDA) is a well-established biomarker of emotional arousal, which is physiologically related to emotion regulation. A quasi-experimental case control study using predefined groups was conducted. Three groups of young people (16-25 years; n = 180) with different self-harm histories were recruited: no self-harm history (n = 62), self-harm ideation last year with no enaction (n = 51) and self-harm enaction last year (n = 67). EDA was measured during three tasks: an auditory tones habituation task, a psychosocial stress task and an emotional images task. Those in the self-harm enaction group elicited a heightened EDA response (hyperreactivity) across two tasks, specifically a slower habituation rate to auditory tones and higher EDA during the psychosocial stress task compared to other groups. High levels of non-response during the emotional images task limited analyses. These findings expand our understanding of the biomarkers for self-harm, specifically emotional arousal in young people who self-harm. Specifically, they suggest that those with a history of self-harm exhibit a heightened electrodermal response to both stressful and non-stressful stimuli compared to those who have no history of self-harm and those who have only thought about self-harm.