Psychometric properties of the short version of the children of alcoholics screening test (CAST-6) among Swedish adolescents

Abstract

Aims: The Children of Alcoholics Screening Test (CAST-6) is a brief screening instrument developed to identify children with parents having problematic alcohol use. The aim of this study was to evaluate the psychometric properties of the CAST-6 among adolescents aged 15–18 years, and also to identify an optimal cut-off score for this age group. Methods: A total of 3000 15 to18 year-olds were randomly selected from a register of postal addresses in Sweden. An invitation letter, including access information to the electronic questionnaire, was sent out by regular mail and 1450 adolescents responded with baseline data. Test-retest reliability within a 2–3-week period was calculated based on the 111 respondents who answered the same questionnaire twice. To determine an optimal cut-off score, a small treatment-seeking sample (n = 22) was recruited from a support group agency to be used as a reference group. Results: The six items of the CAST-6 screening test loaded onto one latent factor with good internal consistency (alpha = 0.88), and excellent test-retest reliability (ICC = 0.93, 95% CI 0.90–0.95). The optimal cut-off score among adolescents was 2 points with a sensitivity of 55% and specificity of 79% (AUROC = 0.71, 95% CI 0.58–0.83). Conclusions: The CAST-6 has good to excellent psychometric properties among adolescents. The identified optimal cut-off score of 2 points should be treated with caution due to study limitations. The CAST-6 can be used in various settings to identify a vulnerable at-risk group of children and adolescents that may be in need of support.