title: Effects of caffeine on alcohol-related changes in behavioural control and perceived intoxication in light caffeine consumers.
abstract: BACKGROUND
  Caffeinated alcoholic beverages have been associated with increased risk of alcohol-related harms. However, few studies have examined these combined effects on behavioural control, which is believed to underlie many of the negative effects of alcohol consumption. In addition, studies have often omitted subjective measures, and none have directly assessed the role of caffeine consumer history.
  
  
  OBJECTIVE
  To examine the combined effects of alcohol and caffeine on measures of behavioural control and perceived intoxication in abstinent, light caffeine consumers.
  
  
  METHODS
  Participants (n = 28; 50% male) attended four sessions at which they consumed one of the following beverages in a randomised order: placebo, alcohol alone (0.6 g/kg), caffeine alone (2.0 mg/kg), and alcohol/caffeine. They completed measures of mood, intoxication, anxiety and alcohol craving before and after a task battery comprising measures of behavioural control and reaction time performance.
  
  
  RESULTS
  Caffeine attenuated alcohol-related performance deficits on stop-signal accuracy, had no effect on go-no-go performance deficits, and worsened accuracy on the Stroop task. Caffeine did not influence absolute changes in perceived intoxication but there was suggestion that caffeine may have changed the nature of intoxication with increases in stimulation.
  
  
  CONCLUSIONS
  Caffeine appears to have mixed effects on alcohol intoxication that are task-dependent. We found increased stimulation in the alcohol/caffeine condition, supporting the contention that caffeinated alcoholic beverages enable an individual to drink for longer. Future research should model real world drinking behaviour by examining how these effects change across multiple drink administrations.
authors.affiliation: School of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol, BS8 1TU, UK. Angela.Attwood@bristol.ac.uk
authors.forename: Angela S
authors.initials: AS
authors.lastname: Attwood
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Rogers
authors.forename: Alia F
authors.initials: AF
authors.lastname: Ataya
authors.forename: Sally
authors.initials: S
authors.lastname: Adams
authors.forename: Marcus R
authors.initials: MR
authors.lastname: Munafò
mesh_terms: D000293:Adolescent; D000328:Adult; D000428:Alcohol Drinking / Q000523:psychology; D000434:Alcoholic Beverages; D000435:Alcoholic Intoxication / Q000523:psychology; D002110:Caffeine / Q000494:pharmacology*; D002492:Central Nervous System Depressants / Q000008:administration & dosage / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D000431:Ethanol / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D055815:Young Adult
chemical_list: D002492:Central Nervous System Depressants; D000697:Central Nervous System Stimulants; D002110:Caffeine; D000431:Ethanol