A neurocognitive examination of impulsivity, inhibitory control and decision making in problem gambling
2017-02-27T04:06:16Z (GMT) by
Problem gambling is increasingly viewed as a behavioural addiction of impaired control. Neurocognitive models of substance-based addictions propose that dysfunction within the fronto-striatal networks underlies the impaired control displayed in addictive disorders. In particular, fronto-striatal dysfunction results in elevated levels of impulsivity and impairments in the key cognitive skills of inhibitory control and decision making. The overall goal of the studies presented in my thesis was to investigate impulsivity, inhibitory control and decision making in problem gambling. Furthermore, recent theoretical models of problem gambling have proposed subtypes of problem gamblers may exist. As such, we examined whether impulsivity, inhibitory control and decision making differed between problem gamblers subtyped according to preferred gambling form. Participants included 39 treatment-seeking problem gamblers and 41 age-, gender- and estimated-IQ-matched healthy controls. In addition, the problem gambling sample was further divided into problem gamblers who prefer either strategic gambling activities (e.g., sports-betting, casino games) or non-strategic gambling activities (e.g., electronic gaming machines). To measure self-reported impulsivity we used the Barratt Impulsiveness Scale and the UPPS-P Impulsivity scale. Inhibitory control was measured using the Stop Signal Task, the Sustained Attention to Response Task, an emotional Stroop task and the Random Number Generation task. Decision making tasks included a Loss Aversion Task and the Iowa Gambling Task (IGT). Additionally, we further analysed IGT performance using the Prospect Valence Learning (PVL) model, which is a cognitive model that quantifies the cognitive, motivational and response style factors involved in decision making. With regard to self-reported impulsivity and inhibitory control, we found that overall problem gamblers reported elevated self-reported impulsivity; however, we did not find strong evidence that problem gamblers differed from controls on any of the inhibitory control measures. Moreover, strategic and non-strategic problem gamblers did not differ from their respective controls on impulsivity or inhibitory control measures. In contrast, on both decision making tasks, problem gamblers performed more poorly than controls, and according to the PVL model, problem gamblers’ IGT performance was associated with a heightened attention to gains and less consistency. Importantly, we found striking differences in decision making between strategic and non-strategic problem gamblers. Strategic problem gamblers did not differ from matched controls on either decision making task; however their IGT choices were associated with greater attention to gain, more sensitivity to losses and less choice consistency (i.e., impulsivity). In contrast, non-strategic problem gamblers performed more poorly on both the IGT and the Loss Aversion task than matched controls, and their IGT choices were associated with less sensitivity to losses. In conclusion, we found no evidence of inhibitory control impairments, despite problem gamblers reporting high impulsivity levels. However, we have highlighted the important underlying cognitive processes involved in problem gamblers’ decision making, which differed according to problem gambling subtype. This thesis demonstrates the key role of impaired decision making in problem gambling and the presence of cognitive differences between subtypes of problem gamblers. Our findings provide a unique contribution to the literature by further highlighting the importance of heterogeneity in problem gambling.