Placebo caffeine reduces withdrawal in abstinent coffee drinkers.

BACKGROUND: Expectancies have been shown to play a role in the withdrawal syndrome of many drugs of addiction; however, no studies have examined the effects of expectancies across a broad range of caffeine withdrawal symptoms, including craving.

AIMS: The purpose of the current study was to use caffeine as a model to test the effect of expectancy on withdrawal symptoms, specifically whether the belief that one has ingested caffeine is sufficient to reduce caffeine withdrawal symptoms and cravings in abstinent coffee drinkers.

METHODS: We had 24-h abstinent regular coffee drinkers complete the Caffeine Withdrawal Symptom Questionnaire (CWSQ) before and after receiving decaffeinated coffee. One-half of the participants were led to believe the coffee was regular caffeinated coffee (the 'Told Caffeine' condition) and one-half were told that it was decaffeinated (the 'Told Decaf' condition).

RESULTS: Participants in the Told Caffeine condition reported a significantly greater reduction in the factors of cravings, fatigue, lack of alertness and flu-like feelings of the CWSQ, than those in the Told Decaf condition.

CONCLUSIONS: Our results indicated that the belief that one has consumed caffeine can affect caffeine withdrawal symptoms, especially cravings, even when no caffeine was consumed.