Caffeine and alertness: in defense of withdrawal reversal

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

The claim that the alerting effects felt by frequent caffeine consumers after caffeine consumption represent withdrawal reversal rather than a net benefit for alertness (with associated effects on cognitive performance) has been variously disputed. This review examines the arguments for and against withdrawal reversal and finds in favor of withdrawal reversal. First, although acutely caffeine abstinent, frequent caffeine consumers show increased alertness and improved cognitive performance after taking caffeine, neither their alertness nor performance exceeds that of placebo-treated noncaffeine consumers or former caffeine consumers. Second, while caffeine may increase alertness, or at least wakefulness, in nonconsumers, this is not against withdrawal reversal as it says nothing about what occurs with frequent consumption. Third, the logic of ‘‘predosing’’ studies as a test of withdrawal reversal is flawed because the effects of caffeine in frequent consumers predosed with caffeine could be due to a failure of the predose to fully reverse withdrawal rather than to a net benefit of the second dose of caffeine. Fourth, failure to find in some (but not all) studies that alertness is lower or cognitive performance is poorer in acutely withdrawn frequent consumers than in nonconsumers is not strong evidence against withdrawal reversal as ‘‘absence of evidence is not evidence of absence.’’ Finally, evidence of faster responding on reaction time tasks and correlations between habitual caffeine and better cognitive function in older age do not contradict withdrawalreversal but instead point to physical performance and, just possibly, neuroprotective effects of caffeine.
Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalJournal of caffeine research
Volume4
Issue number1
Publication statusPublished - 2014

Structured keywords

  • Brain and Behaviour
  • Nutrition and Behaviour

Keywords

  • Caffeine, Tolerance, Withdrawal reversal, Alertness, Cognition, Performance

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