title: Ketamine use among regular tobacco and alcohol users as revealed by respondent driven sampling in Taipei: prevalence, expectancy, and users' risky decision making.
abstract: The popularity of ketamine for recreational use among young people began to increase, particularly in Asia, in 2000. To gain more knowledge about the use of ketamine among high risk individuals, a respondent-driven sampling (RDS) was implemented among regular alcohol and tobacco users in the Taipei metropolitan area from 2007 to 2010. The sampling was initiated in three different settings (i.e., two in the community and one in a clinic) to recruit seed individuals. Each participant was asked to refer one to five friends known to be regular tobacco smokers and alcohol drinkers to participate in the present study. Incentives were offered differentially upon the completion of an interview and successful referral. Information pertaining to drug use experience was collected by an audio computer-assisted self-interview instrument. Software built for RDS analyses was used for data analyses. Of the 1,115 subjects recruited, about 11.7% of the RDS respondents reported ever having used ketamine. Positive expectancy of ketamine use was positively associated with ketamine use; in contrast, negative expectancy inversely associated with ketamine use. Decision-making characteristics as measured on the Iowa Gambling Task using reinforcement learning models revealed that ketamine users learned less from the most recent event than both tobacco- and drug-naïve controls and regular tobacco and alcohol users. These findings about ketamine use among young people have implications for its prevention and intervention.
authors.affiliation: Institute of Epidemiology and Preventive Medicine, College of Public Health, Taipei, Taiwan. ; Department of Public Health, College of Public Health, Taipei, Taiwan. ; Department of Psychiatry, College of Medicine and National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Wei J
authors.initials: WJ
authors.lastname: Chen
authors.affiliation: Institute of Epidemiology and Preventive Medicine, College of Public Health, Taipei, Taiwan. ; Center of Neuropsychiatric Research, National Health Research Institutes, Zhunan, Taiwan.
authors.forename: Te-Tien
authors.initials: TT
authors.lastname: Ting
authors.affiliation: Institute of Epidemiology and Preventive Medicine, College of Public Health, Taipei, Taiwan.
authors.forename: Chao-Ming
authors.initials: CM
authors.lastname: Chang
authors.affiliation: Institute of Epidemiology and Preventive Medicine, College of Public Health, Taipei, Taiwan.
authors.forename: Ying-Chun
authors.initials: YC
authors.lastname: Liu
authors.affiliation: Department of Psychiatry, College of Medicine and National Taiwan University Hospital, Taipei, Taiwan. ; Center of Neuropsychiatric Research, National Health Research Institutes, Zhunan, Taiwan ; Institute of Public Health, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Chuan-Yu
authors.initials: CY
authors.lastname: Chen
keywords: decision making; expectancy; ketamine; respondent-driven sampling (RDS)