An investigation of episodic foresight ability in users of illicit substances

Abstract

The overall objective of this research project was to investigate the cognitive ability of episodic foresight in various drug-using populations. Episodic foresight refers to the uniquely human ability to mentally project the self into the future and pre-experience an event. The first study (in press) was designed to address an identified gap in our understanding of episodic foresight in long-term opiate users. A group of long term opiate users (n = 48) and a group of matched controls (n = 48) were compared on episodic foresight, and the contribution of memory and executive function to this ability were investigated. The results of the first study identified specific episodic foresight impairment in the context of chronic opiate use which was not secondary to memory or executive control processing. Given these findings and recent literature that has begun to explore the cognitive and neural underpinnings of episodic foresight, the primary objective of the second study was to explore whether the deficit in episodic foresight among long-term opiate users identified in Study 1 may be attributable to compromised scene construction and/or self-projection abilities, both of which have been implicated in similar deficits observed in other clinical samples. This study assessed a group of long-term opiate users (n = 35) and demographically matched controls (n = 35). The results confirmed the episodic foresight deficit, and identified a specific impairment in self-projection. The third study aimed to assess whether an episodic foresight deficit would be observed in substance users at the less severe end of the spectrum of substance use. The third study assessed recreational cannabis users (n = 25) and demographically matched controls (n = 45). The results indicated no episodic foresight impairment in this group. Overall, the results of this research project suggest that compromised episodic foresight is apparent in the context of chronic but not recreational substance use. Abreakdown in episodic foresight may therefore represent an important potential mechanism that may contribute to the poor functional, social, and treatment outcomes often associated with chronic substance use.