Abstract

BEHAVIOURAL EFFECTS OF CAFFEINE: CONSIDERATION OF CONTEXTUAL FACTORS

Andrew P. Smith PhD*

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Abstract

Background: There has been extensive laboratory research on the behavioural effects of caffeine. There is still a need to determine whether such effects are obtained with realistic doses, when sugar is added to the drink, and when participants vary in age and personality. The relationship between acceptability and behavioural effects of caffeine also requires further study. Methods: One hundred and twenty-eight participants completed a separate groups, double-blind study examining the effects of 60mg caffeine in coffee and sugar on mood and performance. Associations of the behavioural effects of caffeine and sugar with acceptability, habitual level of caffeine consumption, age and personality were examined. Results: Caffeine was associated with a more positive mood and faster simple reaction time and encoding of new information. These effects did not vary with drink acceptability, time of day, level of habitual caffeine use, age or personality. Sugar had little effect on mood or performance. Conclusion: These results demonstrate that the behavioural effects of caffeine are largely unaffected by contextual factors related to the nature of the drink, regular caffeine usage and individual characteristics of the person.

Keywords: Caffeine; Sugar; Acceptability; Regular Consumption of Caffeine; Personality; Mood; Performance.