Introduction
Psychological drug research field has currently proposed trait and cognitive explanations in the prediction of drug misuse (Jorge, 2006). Personality traits have long been known to be associated with drug use and/or misuse. From disinhibition personality models, Impulsivity and sensation seeking personality variables were implicated. Sensation seeking (SS) and Impulsivity, two highly similar indicators of the construct of disinhibition personality traits, could better predict drug misuse patterns, across different classes of drugs.
Sensation seeking trait refers to the general need for thrills or the willingness to take risks for excitement, a preference for unpredictable situations and a need for novelty. Youths relatively high in sensation seeking may have a biologically based need for stimulation, making them more vulnerable to substance abuse and more susceptible to the reinforcing effects of pleasurable stimuli, or risk behaviours including use or misuse of drugs(Zuckerman, 2007). Many studies had demonstrated that individuals high in sensation seeking appear to be drawn to smoking, alcohol use and use/misuse of illicit drugs (Dom, Hulstijn & Sabbe, 2006; Stoops, Lile & Robbins, 2006). Impulsivity, in contrast, refers to the lack of planning and a tendency to act quickly on impulse without thinking. Impulsivity can predispose to substance abuse, and can result from it. Impulsivity is related to increased stimulus orientation and disinhibited drive-related behaviour. In turn, abused drugs increase Impulsivity by activating catecholaminergic systems related to stimulus-orientation and action. Impulsivity increases susceptibility and/or predisposes to self-administration of cocaine and other strongly reinforcing substances leading to abuse and predicted poor retention in treatment (Moeller, Dougherty, Barrett, Schmitz, Swann & Grabowski, 2001b). Studies have demonstrated that risk behaviours are significantly correlated with one another and often appear in clusters (Winters, Botzet, Fahnhorst, Baumel, & Lee, 2009). In adolescents as well as adults, individual differences in discounting have been linked to risk taking tendencies (impulsivity) such as drug use (Verdejo-Garcia, Lawrence, & Clark, 2008).