Estimating the Size of the Drug Using Population in Three Deep-South Provinces of Thailand : Results from a Service Multiplier and Respondent Driven Sampling Method

Abstract

Background: The Deep-south provinces of Thailand, the border area where the population is majority Malay ethnic, have faced armed-conflicts for the past decade and are a major route of drug trafficking. Several studies reported concerns about drug problems among people in the area but the prevalence of drug users has not been studied. ‘Kratom’ is an alkaloid and the traditional plant originates from South-East Asia. Historically it has been used for its herbal qualities. Presently it is used by adolescents for recreational purposes, and has been reported as the most popular substance in the region for the past decade. Objectives: This study aimed to estimate the size of drug using population in the Deep-south provinces of Thailand. The second objective aimed to compare factors associated with kratom use with and without other substances among kratom users. Design: A cross-sectional survey was conducted in 2016. Males age>18 years who had ever used any drugs including heroin, methamphetamine, cannabis and kratom in past six months were recruited. A respondent-driven sampling method was used to reach the target population. We used the multiplier method to estimate the size of the drug using population. For objective two, we excluded participants who were not currently Kratom users from the analysis. Result: The estimated number of drug users in 2016 in our study setting was 13,545 thus the prevalence of drug users among male population in the same age group was 50.2 per 1,000 population, twice as high as the national ix prevalence. Most drug users lived in Pattani (60.6%) followed by Narathiwat and Yala provinces. The most currently used drug among current drug users was kratom (85.2%) followed by methamphetamine (57.7%) and cannabis (29.2%). More than half (60.6%) of current users consumed more than one type of illicit drugs. Kratom and methamphetamines were the most common combination (25.6%). Use of kratom alone was reported by 38% of users; while kratom co-use use was reported by 62%. The most common combination was kratom and methamphetamines (54%). Being a heavy kratom user increased the odds of heavy methamphetamine use (OR= 4.19 95%CI=2.10-8.33). Five factors were statistically significantly associated with varying patterns of kratom use: living in Pattani province, use with peers, report of having been in treatment during last six months, having history of treatment from an ‘Other Health’ sector and having been in treatment for more than 1 episode, with adjusted ORs of 0.52, 0.39, 2.73, 2.25 and 3.36 respectively. The mean ASSIST score was highest for kratom (22.8) followed by methamphetamine (10.0). Conclusion: Kratom was found the most commonly used substance. The high prevalence of drug users should be considered by stakeholders. The results of this study are useful for policy makers to develop intervention to minimize and control kratom use. Polydrug use among kratom users was demonstrated to be a serious problem in southern Thailand. The combination of kratom and methamphetamine should be considered high risk.