Development of the Thai Cannabis Risky Use Screening Test

Abstract

Cannabis use may affect drug users’ health and vitality, but few cannabis users seek health care assistance. This study’s objective is to develop an instrument to identify cannabis use disorder among Thai people and investigate its psychometric properties. A two-stage mixed-method research design was implemented. The first phase was conducted by literature review, in-depth interviews, a focus group, cognitive testing, and exploratory factor analysis. The second phase was conducted using a two-stage screening procedure in a field survey conducted among 1,120 subjects. The gold standard for diagnosis was based on one psychiatrist according to Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR) criteria. The optimal cut-off point was ⩾9.56 (sensitivity, 92%; specificity, 92%). Confirmatory factor analysis revealed two factors, namely loss of control and impacts of cannabis, with good model fit (comparative fit index [CFI] = 0.926, Tucker–Lewis index [TLI] = 0.909, root mean square error approximation [RMSEA] = 0.049). The final instrument, consisting of 13 items, was named “Thai Cannabis Risky Use Screening Test” or TCRUST.