Trends in the use of illicit substances in Thailand: Results from national household surveys

Introduction and Aims Thailand borders some of the world’s largest methamphetamine and opioid producing countries and trafficking routes. Thailand’s ‘War on Drugs’ campaign was launched in 2003. This study reports trends in illicit substance use in Thailand over the period 2001–2011. Design and Methods National Household surveys on illicit drug use were conducted in 2001, 2003, 2007, 2008 and 2011. A stratified multi‐stage cluster random sampling technique was implemented for each survey. Provinces in four regions were systematically selected using a probability proportionate to the size of the targeted population. Participants were interviewed using structured questionnaires on their history of substance use. Results The prevalence of illicit drug use within the past drastically decreased from 4.5% in 2001 to 1.0% in 2003 (P