(PS11-34) Examining Nociceptive Perception in the Context of Non-suicidal Self-injury Functions

Introduction: Non-suicidal self-injury (NSSI) has been associated with decreases in pain sensitivity and even total pain analgesia. Physical pain and numbness are important to assess in people who engage in NSSI as diminished nociceptive perception during self-injury is associated with an increased likelihood of future suicide attempts. Research on nociceptive perception has found that individuals who engage in NSSI tend to have (a) higher pain thresholds, (b) higher pain tolerances, and (c) lower self-reported pain intensity than those without a history of NSSI. However, most of this research has been done in laboratory settings and have not assessed pain during actual acts of self-injury.

Methods: Using ecological momentary assessment (EMA), data was collected from 40 participants who engaged in NSSI during a two-week period (M_age = 19.26 years, SD_age = 1.65). Each EMA survey assessed for engagement in NSSI, self-reported function for self-injury, as well as physical pain and physical numbness during the NSSI act. Three categories of functions were coded: emotion avoidance, emotion generation, and self-punishment. Pearson’s t-tests were conducted to assess how each self-reported NSSI function relates to physical pain and physical numbness during NSSI engagement.

Results: 143 EMA responses included instances of at least one NSSI behavior across participants. NSSI episodes wherein the self-reported NSSI function related to emotion generation demonstrated lower levels of physical pain (t(140.40) = 2.68, p = 0.008) and higher levels of physical numbness (t(137.54) = -2.37, p = 0.019) compared to episodes without emotion generation functions. The effect sizes, as measured by Cohen’s d, were d = 0.45 and d = 0.40, respectively, indicating small to medium effects. Further, observations with reported self-punishment functions were associated with lower levels of physical numbness (t(65.23) = 2.09, p = 0.041, Cohen's d = 0.40), but not with differences in physical pain (p > 0.05).

Conclusion: NSSI episodes involving emotion generation or self-punishment functions may have diminished nociceptive perception during NSSI. Findings suggest that NSSI function may be a significant risk factor that could aid in identifying who, among those who engage in NSSI, is at risk for an increase in NSSI severity, as well as future suicide attempts.