title: Does caffeine intake enhance absolute levels of cognitive performance?
abstract: The relationship between habitual coffee and tea consumption and cognitive performance was examined using data from a cross-sectional survey of a representative sample of 9003 British adults (the Health and Lifestyle Survey). Subjects completed tests of simple reaction time, choice reaction time, incidental verbal memory, and visuo-spatial reasoning, in addition to providing self-reports of usual coffee and tea intake. After controlling extensively for potential confounding variables, a dose-response trend to improved performance with higher levels of coffee consumption was observed for all four tests (P < 0.001 in each case). Similar but weaker associations were found for tea consumption, which were significant for simple reaction time (P = 0.02) and visuo-spatial reasoning (P = 0.013). Estimated overall caffeine consumption showed a dose-response relationship to improved cognitive performance (P < 0.001 for each cognitive test, after controlling for confounders). Older people appeared to be more susceptible to the performance-improving effects of caffeine than were younger. The results suggest that tolerance to the performance-enhancing effects of caffeine, if it occurs at all, is incomplete.
authors.affiliation: ICRF Health Behaviour Unit, National Addiction Centre, London, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Jarvis
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002110:Caffeine / Q000494:pharmacology*; D002755:Choice Behavior / Q000187:drug effects; D003069:Coffee; D003071:Cognition / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects; D008875:Middle Aged; D011597:Psychomotor Performance / Q000187:drug effects*; D011930:Reaction Time / Q000187:drug effects; D013028:Space Perception / Q000187:drug effects; D013662:Tea; D013850:Thinking / Q000187:drug effects; D006113:United Kingdom
chemical_list: D003069:Coffee; D013662:Tea; D002110:Caffeine