Objective Suicidal ideation is one of the most common mental health issues among younger adults, with the incidence reaching as high as 18%. Younger adults’ suicide crisis may stem from a failure of the acute stress physiological response, but few studies have explored the relationship between suicidal ideation and electrodermal activity (EDA) response under acute stress. The aim of this research was to determine whether EDA differs between suicidal ideators and non-ideators.
Methods A total of 50 college students with (suicidal ideators: n = 26) and without suicidal ideation (non-ideators: n = 24) in the past week were recruited based on items 4 and 5 of the Beck Scale for Suicidal Ideation. The two groups completed the Trier Social Stress Test (TSST), during which their EDA signals were recorded. EDA was assessed using two indicators: the skin conductance level (SCL) and the nonspecific skin conductance responses (NS-SCRs). Multiple linear regression models were fitted to examine the associations between suicidal ideation and the baseline EDA, EDA reactivity, and EDA recovery, controlling for other covariates including age, sex, depression, and trait anxiety (TAI).
Results Compared with the control groups, ideators showed lower baseline EDA (SCL _baseline, β = -0.64, p = 0.007; NS-SCRs _baseline, β = -0.61, p = 0.004) and heightened NS-SCRs reactivity during TSST (NS-SCRs _reactivity, β = 0.55, p = 0.018). There was no significant difference between the two groups in SCL reactivity and EDA recovery.
Conclusions These findings suggest that heightened EDA reactivity to social stress may be a promising psychophysiological biomarker of suicidal ideation, which has significant implications for tracking and intervention in suicide.

Suicidal ideation,Electrodermal activity,Acute Social Stress