Effect of an acute d‐amphetamine administration on context information memory in healthy volunteers: evidence from a source memory task

Rationale Previous research demonstrated a positive effect of d‐amphetamine on long‐term verbal memory. An improvement in memory for contextual information is proposed as a possible mechanism underlying the d‐amphetamine facilitation effect. Objectives A double blind, placebo controlled experiment was used to examine the processes involved in episodic memory affected by an acute administration of d‐amphetamine. We investigated whether positive effects of d‐amphetamine on item memory could be extended to context information by using a source memory paradigm. Methods In a within‐subjects design with two sessions, two study lists were presented in each session and participants were required to make an old/new recognition decision (item memory) and a list discrimination judgement (source memory) after delays of 1 h, 1 day and 1 week. Results Enhancement of item memory after d‐amphetamine intake was observed on delayed tests only, confirming that amphetamine does not affect short‐term memory or memory acquisition, but rather a process operating after initial encoding. Importantly, we found an enhancement in remembering the source of recognized items after d‐amphetamine administration. Conclusion The present study suggests that an acute administration of d‐amphetamine helps to bind different features of an item in memory, in turn leading to an increased ability to recollect both the item and its context. Copyright © 2010 John Wiley & Sons, Ltd.