Development and validation of a brief entrapment scale for adolescents with depression: psychometric evaluation and suicide risk prediction.

BACKGROUND: Suicidal behavior results from desire to escape overwhelming internal emotional distress or intolerable external circumstances. This sense of being trapped has emerged as a key psychological marker of suicide risk. The 16-item Entrapment Scale (ES) offers a comprehensive assessment; however, its length poses challenges for rapid clinical screening. Although efforts have recently been made to develop shortened versions of the ES, no scale has yet been tailored specifically to adolescents with depression, a population at high risk for suicide requiring efficient tools. METHODS: This study developed and validated the Entrapment-Clinical Screening Form (E-CSF), a brief measure designed for clinical screening of entrapment in adolescents with depression. 407 adolescents diagnosed with depression were recruited from a psychiatric outpatient clinic. Participants completed the 16-item ES, Patient Health Questionnaire-9, and other relevant measures. The psychometric properties of the E-CSF (including factor structure, item quality, reliability, validity, and predictive utility) were rigorously evaluated. RESULTS: (1) Confirmatory factor analysis supported a two-factor structure ("internal entrapment" and "external entrapment"), reinforced the conceptual distinction between internal and external sources of entrapment. (2) Based on item response theory analyses, two high-performing items were selected from each factor to form the four-item E-CSF. (3) Reliability analyses indicated excellent internal consistency (Cronbach's α = 0.89). (4) Validity analyses showed that the E-CSF was highly correlated with the full ES (r = .95), and demonstrated comparable associations with depression, anxiety, and related psychological variables. Notably, the E-CSF showed slightly stronger correlations with suicidal ideation and behaviors than did the ES. (5) In terms of suicide risk prediction, the E-CSF effectively distinguished between adolescents with and without suicide risk at the group level. Receiver operating characteristic (ROC) analysis demonstrated good discriminative validity (AUC = 0.81), with an optimal cutoff score of 7. CONCLUSION: The E-CSF is a psychometrically sound, time-efficient, and clinically practical tool for assessing entrapment among adolescents with depression. Its robust reliability, structural validity, and predictive accuracy make it particularly well-suited for use in psychological crisis intervention and public mental health settings. The E-CSF holds promise for rapid identification of high-risk individuals, supporting timely suicide prevention efforts. CLINICAL TRIAL NUMBER: Not applicable.