Episodic foresight deficits in long-term opiate users

Rationale: There is considerable literature showing that opiate use is associated with a range of neurocognitive deficits, including deficits in executive control and episodic memory. However, no study to date has assessed whether these neurocognitive difficulties extend to the ability to mentally time travel into one's personal future. This is a surprising omission given that executive control and episodic memory are considered to be critical for episodic foresight. In addition, opiate-related brain changes have been identified in the neural regions that underlie the capacity for episodic foresight. Objective: In the present study, we assessed how episodic foresight is affected in the context of chronic opiate use, as well as the degree to which any deficits are related to difficulties with executive control and episodic memory. Methods and Results: Forty-eight long-term heroin users enrolled in an opiate substitution program and 48 controls were tested. The results showed that, relative to controls, the clinical group exhibited significant impairment in episodic foresight but not episodic memory (as indexed by an adapted version of the Autobiographical Interview). For executive function, the clinical group was impaired on only one of three measures (Inhibition). Conclusions: These data provide important preliminary evidence that episodic foresight might be particularly susceptible to the neurocognitive effects of opiate use, as the difficulties identified were not secondary to more general executive control or episodic memory impairment. Because a number of widely used relapse prevention protocols require the ability to mentally project into the future, these data have potentially important practical implications in relation to the treatment of substance dependence disorders.