Distress tolerance and lifetime frequency of non-suicidal self-injury (NSSI): A systematic review and meta-analysis.

NSSI has recently been recognized as a significant health issue given its documented association with psychopathology and across a broad spectrum of psychiatric disorders. It has been found that individuals experiencing heightened emotions, which is referred to as an emotional cascade, are more likely to engage in self-injury behaviour due to low levels of distress tolerance (DT). The current meta-analysis using PRISMA guidelines sought to quantify the strength of the association between DT and lifetime frequency of NSSI using 22 eligible studies (N = 14,588; F = 60.7%; age = 23.35 ± 7.30), mainly from the United States. The correlation between emotional DT and NSSI was a small negative correlation (r = -.14), and it was non-significant for behavioural DT and NSSI (r = .02). Also, the effect-size was significant for studies that used interview-based measure of NSSI (r = -.24), and it was non-significant when self-report measures of NSSI (r = -.11) utilized. The association between DT and NSSI was significant and negative across the general population (r = -.47), university students (r = -.17), and inpatients (r = -.27); surprisingly, it was significant and positive among adolescents or high school students (r = .17). The observed effect-sizes were independent of publication year, mean age and its standard deviation, study quality, female proportion, DT, NSSI measures reliability, and clinical status. Future studies on NSSI should consider DT as a spectrum from distress intolerance to distress over-tolerance, given that it seems it has different functions when different samples (e.g., adolescents) are studied.