A comparison of the effects of caffeine following abstinence and normal caffeine use.
BACKGROUND
Caffeine typically produces positive effects on mood and performance. However, tolerance may develop following habitual use, and abrupt cessation can result in withdrawal symptoms, such as fatigue. This study investigated whether caffeine has a greater stimulant effect in a withdrawn state compared to a normal caffeinated state, among moderate daily caffeine consumers.


METHODS
Using a within-subjects design, 17 caffeine consumers (mean +/- sd = 375 +/- 101 mg/day) ingested placebo or caffeine (250 mg) following 30-h of caffeine abstention or normal dietary caffeine use on four separate days. Self-reported mood and performance on choice reaction time, selective attention, and memory tasks were measured.


RESULTS
Caffeine had a greater effect on mood and choice reaction time in the abstained state than in the normal caffeinated state, but caffeine improved selective attention and memory in both states.


CONCLUSIONS
Although improvements in mood and reaction time may best explained as relief from withdrawal symptoms, other performance measures showed no evidence of withdrawal and were equally sensitive to an acute dose of caffeine in the normal caffeinated state.
Department of Radiology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157, USA.
Merideth A
MA
Addicott
Paul J
PJ
Laurienti
D000328:Adult; D000339:Affect / Q000187:drug effects*; D001288:Attention / Q000187:drug effects*; D002110:Caffeine / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects*; D011597:Psychomotor Performance / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D013375:Substance Withdrawal Syndrome / Q000523:psychology; D013997:Time Factors
D000697:Central Nervous System Stimulants; D002110:Caffeine