Abstract
Substance abuse has been an important social and public health problem in Thailand for decades. The National Household Survey on Substance and Alcohol Use in Thailand, which has been conducted six times, shows that substance abuse has steadily increased.
Extrapolated country-wide in recent data, the estimated number of people who have used at least one addictive substance at some time in their lives was 2,964,444 or 5.8% of the total population aged 12 - 65 years. Kratom, Methamphetamine, methamphetamine hydrochloride crystal (ice), and cannabis were the most prevalent substances of abuse.

Historical documentation and policy reports were used in this study. The objectives of this study were to complete a document review, determine the effectiveness of previous measures to control illegal substance abuse in Thailand, and consider options for the future.

Controlling illegal substance abuse in the future and minimizing total harm requires a delicate balance of efforts to reduce the prevalence, quantity, and harmful effects of substances. Drug policy interventions should be continually evaluated for their effectiveness.
The strategies relevant to drug policy, apart from primary prevention, are health services for chronic drug users, reform of criminal sanctions against drug addicts, and legalization of kratom.

Keywords: substance abuse policy, Thailand