Why there is a discrepancy between self-report and objective measures of prospective memory in recreational drug users?

Extensive research has been conducted to investigate the effects of illegal drug use on prospective memory (PM), however, the findings are rather inconclusive. While the studies with lab-based PM testing methods demonstrated consistent findings with drug users scoring worse than non-users on various PM tests, the studies employing self-report measures of PM, have shown mixed findings as illegal drug users exhibited PM deficits in some studies, but not in others. These findings show little or no overlap between lab-based and self-reported PM performance in drug users. The current study aimed to understand how drug users manage to remember and execute delayed intentions in everyday life from their point of view, whether they use any specific strategies to perform such intentions and the confounding factors that might have an impact on their PM performance. Therefore, it has the potential to unfold the discrepancy between self-report and lab-based PM measures in drug users. Seven drug users, aged between 29 to 41, were interviewed on different components of PM (i.e., short-term memory, long-term memory, attention, and cognitive shifting), using the explicitation interview technique. Theoretical thematic analysis was employed to analyse the data. The results revealed that the perceived importance of the intention, cues availability at the retrieval phase, time awareness, and attention play a crucial role in PM, thus impairments in such domains might be associated with poor PM performance in drug users. The results further showed that drug users might be impaired in metacognition which is why there is a discrepancy between self-report and lab-based PM measures in drug users. Overall, this study highlights the importance of mentioned cognitive functions in PM and metacognitive impairment in drug users which may contribute to the maintenance of drug use despite adverse consequences and the transition from recreational drug use to addiction.