Available online at www.sciencedirect.com Drug and Alcohol Dependence 95 (2008) 81–89 Impulsivity in Hong Kong-Chinese club-drug users Natalie J. Loxton a , Venice L.-N. Wan b , Ada M.-C. Ho b,c , Ben K.-L. Cheung d , Nicole Tam b , Freedom Y.K. Leung e , Alfreda Stadlin b,c,∗ a School of Psychology, The University of Queensland, Brisbane, Queensland, Australia b Department of Anatomy, Chinese University of Hong Kong, Hong Kong c School of Medical Science, Griffith University, Queensland, Australia d Substance Abuse Assessment Clinic, Kwai Chung Hospital, Tsuen Wan, N.T., Hong Kong e Department of Psychology, Chinese University of Hong Kong, Hong Kong Received 10 July 2007; received in revised form 17 November 2007; accepted 17 December 2007 Available online 1 February 2008 Abstract To investigate the relationship between personality, club-drug use and high-risk drug-related behaviour, 360 club-drug users and 303 non-drug users in Hong Kong were assessed on measures of two impulsivity dimensions, reward drive and rash impulsivity, and a related trait of punishment sensitivity. The most frequently used drugs were ketamine, ecstasy, and cannabis, with the majority of participants using two or more drugs on any one occasion. Club-drug users were more rash-impulsive and reward-driven, and less punishment-sensitive than non-drug users (p < 0.001). Rash impulsivity, but not reward drive or punishment sensitivity, was significantly (p < 0.001) associated with risky drug-related behaviour. There was no association between any personality traits and preferred drug. These findings suggest that, while those who use club drugs are generally more impulsive and less punishment-sensitive, some discrete facets of impulsivity are associated with differing patterns of drug-use behaviour. © 2007 Elsevier Ireland Ltd. All rights reserved. Keywords: Ketamine; Ecstasy; Cannabis; Personality; Reward; Impulsivity 1. Introduction The use of psychoactive substances such as ketamine, 3,4-methylenedioxy-methamphetamine (MDMA; ‘ecstasy’), methamphetamine (‘ice’) and cannabis has become increasingly popular among young Hong Kong drug users (Joe Laidler, 2005). In particular, the use of ketamine has risen dramatically, from less than one percent of drug users under 21 in 1999 to 61% in 2005, while ecstasy use increased from 13 to 53% over this period (Central Registry of Drug Abuse, 2005). At the same time there has been a rise in the co-occurrence of risky behaviour, such as crossing the border into mainland China to take drugs, which is commonly associated with unprotected sexual activities (Lau et al., 2007). An increase in polydrug use in cross-border users, with some users seeking to heighten their drug-taking experi- ence by mixing ecstasy with ketamine, has also been reported ∗ Corresponding author at: School of Medical Science, Griffith University, Gold Coast Mail Centre, PMB50, Southport QLD 4222, Australia. Tel.: +61 7 555 28215; fax: +61 7 555 28908. E-mail address: a.stadlin@griffith.edu.au (A. Stadlin). (Joe Laidler, 2005). However, despite growing knowledge of the patterns of club-drug use in Hong Kong (and other countries) far less is known about individual differences among those who use club drugs, particularly ketamine. A number of models of addiction refer to at least two “impulsivity-related” dimensions associated with the use and abuse of alcohol and other drugs (Dawe et al., 2004; de Wit and Richards, 2004; Verheul et al., 1999). Although using slightly different labels, such models generally refer to a “reward drive” dimension and a “rash impulsivity” (sometimes referred to as “disinhibition”) dimension. Reward drive refers to individual differences in attending to and approaching appetitive stimuli (Gray and McNaughton, 2000). The underlying motivational system of reward drive is referred to as the Behavioural Acti- vation System (BAS) and is associated with activity in the mesolimbic dopamine system (e.g., Beaver et al., 2006). Reward drive is typically measured using self-report questionnaires, such as Carver and White’s (1994) BAS scales, and behavioural mea- sures, such as the Card Arrangement Reward Responsiveness Objective Test (CARROT: Powell et al., 1996). The second dimension, “rash impulsivity”, refers to the tendency to act 0376-8716/$ – see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.drugalcdep.2007.12.009