title: The acute effects of d-amphetamine and methamphetamine on attention and psychomotor performance.
abstract: BACKGROUND
  It is not clear how the deleterious effects of amphetamines on driving performance are mediated in terms of select cognitive processes.
  
  
  OBJECTIVE
  The current three separate experiments assessed the acute effects of an oral dose of either 0.42-mg/kg d-amphetamine, d,l-methamphetamine and d-methamphetamine on driving-related cognitive functions in a total of 60 healthy non-fatigued adults.
  
  
  METHODS
  Three separate repeated measures counterbalanced, double-blind, placebo-controlled designs were employed in which 20 volunteers completed two treatment conditions, either d-amphetamine, d,l-methamphetamine or d-methamphetamine and placebo. Performance was assessed on a range of attentional, psychomotor and perceptual speed tasks.
  
  
  RESULTS
  Mean blood concentrations at 120-, 170- and 240-min postdrug administration were 83, 98 and 96 ng/ml, respectively, for d-amphetamine, 90, 95 and 105 ng/ml, respectively, for d,l-methamphetamine and 72, 67 and 59 ng/ml, respectively, for d-methamphetamine. The amphetamines, in general, improved various aspects of attention (Digit Vigilance, Digit Symbol Substitution Test and Movement Estimation Performance) with some evidence to suggest possible enhancement in psychomotor functioning (Tracking ability) and perceptual speed (Inspection Time).
  
  
  CONCLUSIONS
  The current series of studies primarily provides evidence of low-level amphetamine-related enhancement of function; however, it also provides evidence of less conservative movement estimation that might contribute to amphetamine-related road fatalities.
authors.affiliation: Drugs and Driving Research Unit, Brain Sciences Institute, Swinburne University of Technology, 400 Burwood Rd, Hawthorn, Victoria 3122, Australia. bsilber@swin.edu.au
authors.forename: Beata Y
authors.initials: BY
authors.lastname: Silber
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Croft
authors.forename: Katherine
authors.initials: K
authors.lastname: Papafotiou
authors.forename: Con
authors.initials: C
authors.lastname: Stough
mesh_terms: D000284:Administration, Oral; D000328:Adult; D019969:Amphetamine-Related Disorders / Q000097:blood / Q000523:psychology*; D001288:Attention / Q000187:drug effects*; D001334:Automobile Driving / Q000523:psychology*; D003913:Dextroamphetamine / Q000493:pharmacokinetics / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008694:Methamphetamine / Q000493:pharmacokinetics / Q000494:pharmacology*; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000187:drug effects*; D011930:Reaction Time / Q000187:drug effects; D013237:Stereoisomerism
chemical_list: D008694:Methamphetamine; D003913:Dextroamphetamine