Development and validation of a scale to measure social isolation in adolescents

Background: There is a lack of questionnaires specifically designed to assess social isolation in adolescents. We developed and validated a self-report measure of social isolation in adolescents, the Social Isolation Questionnaire (QIS).

Methods: A literature review on social isolation and mental health in adolescents indicated 20 questions to form QIS. Two cross-sectional surveys with 48 and 1,135 adolescents, respectively, evaluated the reproducibility and validity of QIS.

Results: The Bland-Altman plot did not indicate a systematic difference between measurements 15 days apart. Bartlett’s sphericity test verified a correlation between the questions and the Kaiser-Meyer-Olkin test showed good adequacy (0.896) to the factor analysis. Exploratory factor analysis suggested the exclusion of three questions (loading factors <0.3), and eigenvalues (4.9 to 0.8) indicated that the questionnaire should be composed of three factors (dimensions). The Cronbach’s alpha indicated high internal consistency of the 17 questions (0.850 overall; Dimensions: 0.815 ‘feeling of loneliness’; 0.760 ‘friendship’; and, 0.680 ‘Family support’). The QIS score ranged from 0 to 131 (maximum social isolation score). Correlation between QIS and depressive symptoms (r=0.543) indicated the construct validity of QIS.

Limitations: We evaluated QIS in the Portuguese version, thus translation and cultural adaptation are necessary to evaluate the questionnaire in other settings.

Conclusions: We constructed and validated the QIS questionnaire, a self-administered questionnaire to assess social isolation in adolescents, composed of three dimensions; feeling of loneliness, friendship and family support. The QIS questionnaire seems a very promising tool to support practitioners and researchers in assessing social isolation among adolescents.