Simulated opioid withdrawal engenders risk-prone choice: A comparison of intravenous and intranasal-using populations

Risk-sensitive foraging theory refers to a group of different models that predict the occurrence of risk-prone behavior; therefore, these models may help to characterize the risky behavior that is a hallmark of opioid dependence. The daily energy budget (DEB) rule, one model of risk-sensitivity, suggests that foragers will prefer highly variable food sources over less variable ones when all current options provide means that are insufficient to meet metabolic requirements. The tenets of the DEB rule were tested in the context of opioid dependence, the primary hypothesis being that opioid withdrawal may foster risky choice. Intravenous and intranasal-using opioid-dependent patients enrolled in a buprenorphine treatment program read scripts simulating opioid-agonist and -antagonist symptoms, and then made a series of decisions between two different opioid dealers. One dealer provided a constant source of heroin, and the other, a variable source. Separate measures were utilized to expose participants to either variability in delay of opioids or quantity of opioids. Participants were also required to complete a money questionnaire in which two hypothetical slot machines differed in respect to payoff amounts and probabilities. Results demonstrate that preference for the risky option was mediated by hypothetical drug deprivation in all circumstances, but this effect was more considerable in opioid-dependent participants who used intravenously. The current findings suggest that intravenous delivery places greater metabolic constraints on the user and therefore engenders greater risk-taking during withdrawal. The DEB rule is applicable to opioid dependence and provides a useful framework from which to examine the behaviors associated with opioid withdrawal.