Effects of caffeine on performance and mood: withdrawal reversal is the most plausible explanation
- 3.8k Downloads
Although it is widely believed that caffeine can enhance human performance and mood, the validity of this belief has been questioned, giving rise to debate. The central question is whether superior performance and mood after caffeine represent net benefits, or whether differences between caffeine and control conditions are due to reversal of adverse withdrawal effects.
To provide a focussed review of relevant experimental studies with the aim of clarifying current understanding regarding the effects of caffeine on human performance and mood.
To avoid the shortcomings of standard placebo-controlled studies, which are ambiguous due to failure to control for the confounding influence of withdrawal reversal, three main experimental approaches have been employed: studies that compare consumers and low/non-consumers, pre-treatment and ad lib consumption studies, and long-term withdrawal studies.
Of the three approaches, only long-term withdrawal studies are capable of unambiguously revealing the net effects of caffeine. Overall, there is little evidence of caffeine having beneficial effects on performance or mood under conditions of long-term caffeine use vs abstinence. Although modest acute effects may occur following initial use, tolerance to these effects appears to develop in the context of habitual use of the drug.
Appropriately controlled studies show that the effects of caffeine on performance and mood, widely perceived to be net beneficial psychostimulant effects, are almost wholly attributable to reversal of adverse withdrawal effects associated with short periods of abstinence from the drug.
KeywordsCaffeine Performance Mood Sleep restriction Withdrawal reversal Fatigue Alertness
- Gilliland K, Bullock W (1984) Caffeine: a potential drug of abuse. Haworth, New YorkGoogle Scholar
- Griffiths RR, Juliano LM, Chausmer AL (2003) Caffeine: pharmacology and clinical effects. In: Graham AW, Schultz TK, Mayo-Smith MF, Ries RK, Wilford BB (eds) Principles of addiction medicine, 3rd edn. American Society of Addiction Medicine, Chevy Chase, MD, pp 134–193Google Scholar
- Haskell CF, Kennedy DO, Wesnes KA, Scholey AB (2005) Cognitive and modd improvements of caffeine in habitual consumers and habitual non-consumers of caffeine. Psychopharmacology (in press)Google Scholar
- Heatherley SV, Hancock KMF, Rogers PJ (2005a) Psychostimulant and other effects of caffeine in 9- to 11-year-old children. J Child Psychol Psychiatry (in press)Google Scholar
- James JE (1997) Understanding caffeine: a biobehavioral analysis. Sage, Thousand Oaks, CAGoogle Scholar
- James JE (2003) Caffeine, mental performance and mood. In: Watson D (ed) Performance functional foods. Woodhead, London, pp 168–194Google Scholar
- Pfeifer RW, Notari RE (1988) Predicting caffeine plasma concentrations resulting from consumption of food or beverages: a simple method and its origin. Drug Intel Clin Pharm 22:953–959Google Scholar
- Rogers PJ, Stephens S, Day JEL (1998) Contrasting performance effects of caffeine after overnight and chronic caffeine withdrawal. J Psychopharmacol 12:A13Google Scholar
- van Duinen H, Lorist MM, Zijdewind I (2005) The effect of caffeine on cognitive task performance and motor fatigue. Psychopharmacology (in press)Google Scholar