Effect of Unobserved Contextual Factors on the Prevalence of New Psychoactive Substance Use in Thailand

Abstract

Objective: To explore the associations of characteristics of the cluster environment with new psychoactive substances (NPS) use in Thailand. Materials and Methods: A cross-sectional study was done on 30,411 Thai people, stratified in multi-stage cluster sampling. Trained interviewers conducted a semi-structured interview in 2016. A multilevel binary logistic regression model was employed to estimate the effects of the cluster environment on the NPS use. Results: NPS was widely used. The past month prevalence was 13.6%, and habitual use was 4.4%. Clustering significantly affects the spread of NPS use. Controlling for cluster effects, a likelihood of current NPS use was associated with elementary education, occupation, and reported health problems. While a higher likelihood of habitual NPS use was associated with elementary education, employed, and perceived mental health problem. Conclusion: NPS use was influenced by characteristics of the cluster environment. Therefore, demand reduction strategies should be designed based on a consideration of the impact of cluster context on NPS use behaviors. Keywords: Cluster effect, New psychoactive substance, NPS, Thailand