Psychometric Properties of the Turkish Intolerance of Uncertainty Index-A in a High-Risk Clinical Adolescent Sample

Objective: Intolerance of uncertainty (IU) is a transdiagnostic cognitive construct associated with anxiety, emotional dysregulation, and psychopathology across multiple clinical conditions. This study aimed to adapt the Intolerance of Uncertainty Index A (IUI-A) into Turkish and evaluate its psychometric properties in a high-risk clinical adolescent sample. Methods: One hundred forty adolescents aged 12–17 years (Mage = 15.71, SD = 1.39; 84.3% female) were recruited from a Child and Adolescent Psychiatry Outpatient Clinic. The sample comprised adolescents presenting with suicidal ideation without a prior attempt (SI; n = 42, 30%) or a history of at least one suicide attempt (SA; n = 98, 70%). The majority met criteria for at least one psychiatric diagnosis, with depressive disorder (77.1%) and anxiety-spectrum conditions most prevalent. Analyses included exploratory and confirmatory factor analysis, internal consistency estimation, and assessments of convergent, discriminant, and known-groups validity. Results: EFA supported a two-factor model (Inhibitory IU and Prospective IU) explaining 61.04% of the variance. CFA indicated partially acceptable fit (χ2/df = 2.48, RMSEA = 0.102, CFI = 0.900, TLI = 0.882, SRMR = 0.054), with RMSEA and TLI falling outside conventional thresholds. Internal consistency was strong (α = 0.933, ω = 0.935). IUI-A scores correlated strongly with the IUS-12, and the SA group scored significantly higher on both IU subscales, with group differences persisting after adjustment for key covariates. Conclusion: The Turkish IUI-A provides preliminary, though methodologically provisional, evidence of validity and reliability for assessing IU in high-risk adolescent populations, with several limitations requiring further investigation.