Lifetime Prevalence of Nonsuicidal Self-Injury in Adolescents: Reliability of a Dichotomous Survey Item.

INTRODUCTION

Nonsuicidal self-injury (NSSI) is a widespread phenomenon among adolescents. Accurate estimates of prevalence rates when screening for NSSI are essential both in research and clinical settings. However, high variability raises the question of the reliability of self-reported NSSI prevalence.

METHODS

The reliability of a dichotomous survey item on history of NSSI was investigated longitudinally using data from five time points across 16 months in a community sample (N = 253) of Swedish adolescents (age M = 14.21 years, SD = 0.56, 58.5% female).

RESULTS

About one in five participants (18.97%) changed their answer compared to their initial response. Of those who answered negatively on lifetime prevalence of NSSI at baseline, 8.95% later acknowledged NSSI, while 57.69% of those initially acknowledging NSSI later answered negatively. Fleiss' kappa across all five measurements indicated moderate agreement. Cohen's kappa between baseline and 12 months indicated moderate agreement.

CONCLUSIONS

In this adolescent sample, the reliability of a single-item question on NSSI history was moderate. More than half of those who initially acknowledged a history of NSSI answered negatively at a later time point. Interpretation of self-reported lifetime prevalence rates of NSSI in adolescents using dichotomous survey items needs to be made cautiously.