Effects of amphetamine on retrieval of memory for emotional stimuli

Abstract

Aims: Drugs of abuse have been shown to affect memory in both animals and humans. However, little is known about drug effects specifically on emotional memory in humans. Stimulant drugs increase positive mood, and as such it is possible that they could preferentially enhance either encoding or retrieval memory for positive emotional stimuli. In this study we investigated the effects of d-amphetamine (AMP) on retrieval of memory for emotional material in humans. We hypothesized that AMP would enhance retrieval of emotional material, particularly for positive emotional stimuli, possibly through its effects on mood. Methods: Participants attended an encoding session in which they viewed standardized positive, neutral, and negative pictures from the International Affective Picture System (IAPS; Lang et al., 1999). Exactly 48h later they attended a retrieval session testing their memory of these stimuli. A between-subject design was utilized in which participants were randomly assigned to receive either AMP (20mg) or placebo (PL) during encoding and either AMP or PL during retrieval. Results: The results presented here are limited to the AMP or PL at retrieval. Data collection is currently ongoing, and to date 22 participants have received AMP in the retrieval session and 13 participants have received PL. Preliminary results show that, regardless of drug administered at encoding, participants receiving AMP at retrieval showed enhanced memory for studied items (p= .036), as well as increased false memory (p= .019), but thus far these effects are not specific to emotional stimuli. Conclusions: As data collection progresseswewill testwhether AMPpreferentially altersmemory for positive stimuli, andwhether memory is related to subjective mood response to AMP. We hypothesize that greater AMP-induced positive moodwill be associatedwithpreferentialmemory forpositive stimuli, thusproviding a potentialmechanism throughwhichAMPeffects onmemorymay promote further use. Financial support: Research supported by NIDA grants R21 DA031796 and F32 DA033756.