Abstract:

Today, drug abuse is closely being watched by most of society. It has been found that risky decision-making deficit is one of the main characteristics of drug abuse. Drug abusers are facing increasingly negative consequences in their personal, emotional, professional, and social lives. However, they still prefer to choose immediate reward, and it is difficult for them to make adaptive decisions. Several studies have shown that risky decision-making abilities of heroin addicts are impaired, but few studies have focused on the impact of different levels of monetary reward on risky decision-making for heroin addicts during abstinence and whether such effects are regulated by type of monetary reward. Therefore, this study used the balloon analogue risk task to examine the effects of different levels of hypothetical and real money rewards on risky decision-making in the abstinent heroin user.

Two experiments were included in the study. In Experiment 1, a hypothetical reward was used. however, the participants were asked to imagine the money prizes obtained in the experiment as real money rewards and to obtain as much profit as possible. The results showed that the main effect of the reward magnitude was significant. Post-hoc testing showed the average adjusted pumps (the mean number of pumps for balloons that did not pop) and the total number of popped balloons were significantly less under the 1-cent reward condition compared with the 25-cent reward condition. The main effects of the group were significant, and post-hoc testing showed that the average adjusted pumps and the total number of popped balloons were significantly higher for the abstinent heroin users compared with the non-heroin users. The interaction between the reward magnitude and the group was not significant. Experiment 2 used real rewards. The final rewards of the participants were converted according to their performance in the experimental task. The results showed that the main effect of reward magnitude was marginal significant for the average adjusted pumps and the main effect of the reward magnitude was significant for the total number of popped balloons. Post-hoc testing showed the average adjusted pumps and the total number of popped balloons were significantly higher under the 1-cent reward condition compared with the 25-cent reward condition. The main effects of the group were significant, and post-hoc testing showed that the average adjusted pumps and the total number of popped balloons for the abstinent heroin users were significantly smaller compared with the non-heroin users. The interaction between the reward magnitude and the group was not significant.

The data suggest that risk-taking behavior is modulated by reward type and magnitude of monetary rewards. Overall, participants make more risky decisions on the BART with increased magnitude of hypothetical monetary rewards. However, this trend is completely reversed under the real monetary reward condition. In addition, compared with the non-heroin user, abstinent heroin users make less “optimal” decisions on the BART under the hypothetical monetary reward condition, while they exhibit greater risk aversion on the BART under real monetary rewards condition.

Key words: the abstinent heroin users, risky decision-making, monetary reward magnitude, balloon analogue risk task