Investigation of prevalence of substance use disorders using direct and indirect methods and factors affecting initiation of substance use

Substance Use Disorders (SUDs) are among some of the major health problems in different societies, especially in Iran, resulting in devastating outcomes. This study was conducted to investigate the prevalence of SUDs using both direct and indirect (network scale-up (NUS) and cross-wise model (CM) methods and to identify the factors affecting initiation of substance use. The study was conducted among people aged 15–69 years in Kermanshah, Iran, with a total of 6127 people selected utilizing a stratified sampling method. The prevalence of SUDs was estimated at 3.85% by direct CM, 11.05% by indirect CM and 10.07% by NUS. The results of multivariate logistic regression revealed that the most important factors in increasing the chance of substance use were history of substance use in the family, mental diseases, poor economic status, and age group of 31–45 years. Regarding the almost three-fold prevalence of indirect methods for estimating the prevalence of SUDs compared to direct methods on the one hand and the high prevalence of substance use in the province on the other, special prevention health programs are required by considering the groups at risk.