title: Pre-encoding administration of amphetamine or THC preferentially modulates emotional memory in humans.
abstract: BACKGROUND
  Many addictive drugs are known to have effects on learning and memory, and these effects could motivate future drug use. Specifically, addictive drugs may affect memory of emotional events and experiences in ways that are attractive to some users. However, few studies have investigated the effects of addictive drugs on emotional memory in humans.
  
  
  OBJECTIVE
  This study examined the effects of the memory-enhancing drug dextroamphetamine (AMP) and the memory-impairing drug Δ(9)-tetrahydrocannabinol (THC) on emotional memory in healthy volunteers.
  
  
  METHODS
  Participants completed three experimental sessions across which they received capsules containing placebo and two doses of either AMP (10 and 20 mg; N = 25) or THC (7.5 and 15 mg; N = 25) before viewing pictures of positive (pleasant), neutral, and negative (unpleasant) scenes. Memory for the pictures was assessed 2 days later, under drug-free conditions.
  
  
  RESULTS
  Relative to placebo, memory for emotional pictures was improved by AMP and impaired by THC, but neither drug significantly affected memory for unemotional pictures. Positive memory biases were not observed with either drug, and there was no indication that the drugs' memory effects were directly related to their subjective or physiological effects alone.
  
  
  CONCLUSIONS
  This study provides the first clear evidence that stimulant drugs can preferentially strengthen, and cannabinoids can preferentially impair, memory for emotional events in humans. Although addictive drugs do not appear to positively bias memory, the possibility remains that these drugs' effects on emotional memory could influence drug use among certain individuals.
authors.affiliation: Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S. Maryland Ave., MC3077, Chicago, IL 60637, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Ballard
authors.forename: David A
authors.initials: DA
authors.lastname: Gallo
authors.forename: Harriet
authors.initials: H
authors.lastname: de Wit
mesh_terms: D000293:Adolescent; D000328:Adult; D018592:Cross-Over Studies; D003913:Dextroamphetamine / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D013759:Dronabinol / Q000008:administration & dosage / Q000494:pharmacology*; D004644:Emotions; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects*; D055815:Young Adult
chemical_list: D013759:Dronabinol; D003913:Dextroamphetamine