The aims of this study were to develop the Adolescents Self-injury Tendency Scale (ASITS) under peer influence, and test the reliability and validity of this scale.

A primary questionnaire was developed using a literature review, semi-structured interviews, and expert evaluation. Afterward, 1 938 middle and high school students were surveyed with the initial questionnaire, and ASITS was formulated through item analysis and exploratory factor analysis. Furthermore, we conducted confirmatory factor analysis in the second sample (n=3 160) and tested the scale’s reliability and validity.

ASITS comprised 4 factors and 15 items. The model showed good fit (RMSEA=0.04, SRMR=0.01, CFI=0.98, TLI=0.97). Cronbach’s α for the total scale and each factor ranged from 0.72 to 0.84. The criterion validity showed that ASITS was positively correlated with self-injurious behavior, depression-anxiety-stress symptoms, loneliness and peer pressure (r=0.38,0.31, 0.34, 0.22, P<0.001), and negatively correlated with core self-evaluation (r=-0.34, P<0.001).

ASITS has good reliability and validity, thus providing a reliable tool for evaluating adolescents’ tendency to inflict self-injury under peer influence.