CAFFEINE DEPRIVATION AFFECTS VIGILANCE PERFORMANCE AND MOOD

The effects of brief caffeine deprivation on vigilance performance, mo od, and symptoms of caffeine withdrawal were studied in habitual coffe e drinkers. Thirty male and female coffee drinkers were tested twice a t midday (1130 to 1330 hours) after mornings in which they either cons umed caffeinated beverages ad lib or abstained. Vigilance performance was tested with a 30-min computerized visual monitoring task. Mood and withdrawal symptom reports were collected by questionnaires. Caffeine deprivation was associated with impaired vigilance performance charac terized by a reduction in the percentage of targets detected and an in crease in response time, and by subjective reports of decreased vigor and increased fatigue and symptoms characterized by sleepiness, headac he, and reduced ability to work. Even short periods of caffeine depriv ation, equivalent in length to skipping regular morning coffee, can pr oduce deficits in sustained attention and noticeable unpleasant caffei ne-withdrawal symptoms in habitual coffee drinkers. Such symptoms may be a common side-effect of habitual caffeine consumption that contribu tes to the maintenance of this behavior. (C) 1998 Elsevier Science Inc .