Social Isolation in Turkish Adolescents: Translation, Cross-Cultural Adaptation, and Validation of the Social Isolation Questionnaire

<b>Objectives</b>: Social isolation is an important public health issue that is becoming increasingly prevalent among adolescents today. Recognizing the risk of social isolation in children and adolescents during their developmental years can contribute to the prevention of depression and anxiety disorders, as well as risky behaviors such as suicide and substance abuse. Valid and reliable measurement tools are needed to assess social isolation in adolescents. There is a lack of surveys to identify gaps in social isolation among Turkish adolescents. This study aims to adapt the Social Isolation Questionnaire (QIS) scale, which was developed for adolescents, to Turkish culture and to evaluate its psychometric properties. <b>Methods</b>: This descriptive and methodological study was conducted between July and November 2024 with 1922 adolescents. Data were collected using an introductory information form, the QIS, and the UCLA Loneliness Scale. In the evaluation of the data, explanatory and confirmatory factor analysis, Cronbach's alpha, split-half, item-total score correlation, and test-retest analysis were used. <b>Results</b>: The average age of the adolescents was 13.97 ± 1.67 years (min = 12, max = 17). A total of 50.6% of the adolescents were male and 49.4% were female. A total of 81.2% of the adolescents had a nuclear family structure. Exploratory factor analysis revealed a three-factor structure explaining 55.97% of the variance. The factor loadings were greater than 0.30, and all fit indices were greater than 0.90. The total Cronbach's α value of the scale was 0.83, while the values for the subdimensions ranged from 0.73 to 0.75. <b>Conclusions</b>: The Turkish version of the QIS is a valid and reliable measurement tool for assessing social isolation in adolescents. This questionnaire can be used by health professionals and researchers to identify adolescents at risk of social isolation and plan appropriate mental health interventions. This questionnaire can be used in studies focusing on adolescent mental health and well-being, contributing to the development and implementation of strategies in line with the Sustainable Development Goals.