caa a22 4500 469120002 CHVBK 20180323133136.0 cr unu---uuuuu 170328e19920701xx s 000 0 eng 10.1007/BF02245285 doi (NATIONALLICENCE)springer-10.1007/BF02245285 Caffeine tolerance and choice in humans [Elektronische Daten] [Suzette Evans, Roland Griffiths] Thirty-two healthy subjects with histories of moderate caffeine consumption abstained from dietary caffeine throughout the study. Subjects were stratified into two groups based on several factors including caffeine preference, which was assessed using a caffeine versus placebo choice procedure. Subsequently, subjects received either caffeine (300 mg t.i.d.) or placebo (placebo t.i.d.) for 18 consecutive days, and thereafter were exposed again to a caffeine versus placebo choice procedure. The study documented tolerance development to the subjective effects of caffeine: after chronic dosing, administration of caffeine produced significant subjective effects in the chronic placebo group but not in the chronic caffeine group. The study also provided indirect evidence for tolerance development: during chronic dosing, the chronic caffeine and placebo groups did not differ meaningfully on ratings of mood and subjective effect. When subjects were categorized into caffeine choosers or nonchoosers, caffeine choosers tended to report positive subjective effects of caffeine and negative subjective effects of placebo. Nonchoosers, in contrast, tended to report negative subjective effects of caffeine. Chronic caffeine did not alter the reinforcing effects of caffeine as assessed by caffeine versus placebo choice, possibly because the relatively short duration of caffeine abstinence in the placebo condition was not sufficient to result in maximal withdrawal effects after termination of the relatively high caffeine dose. This study provides the clearest evidence to date of complete tolerance development to a CNS effect of caffeine in humans. Springer-Verlag, 1992 Caffeine nationallicence Tolerance nationallicence Reinforcement nationallicence Physical dependence nationallicence Chronic exposure nationallicence Subjective effects nationallicence Humans nationallicence Evans Suzette Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Behavioral Biology Research Center, 5510 Nathan Shock Dr., Suite 3000, 21224, Baltimore, MD, USA aut Griffiths Roland Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Behavioral Biology Research Center, 5510 Nathan Shock Dr., Suite 3000, 21224, Baltimore, MD, USA aut Psychopharmacology Springer-Verlag 108/1-2(1992-07-01), 51-59 0033-3158 108:1-2<51 1992 108 213 https://doi.org/10.1007/BF02245285 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02245285 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Evans Suzette Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Behavioral Biology Research Center, 5510 Nathan Shock Dr., Suite 3000, 21224, Baltimore, MD, USA aut NATIONALLICENCE 700 1- Griffiths Roland Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Behavioral Biology Research Center, 5510 Nathan Shock Dr., Suite 3000, 21224, Baltimore, MD, USA aut NATIONALLICENCE 773 0- Psychopharmacology Springer-Verlag 108/1-2(1992-07-01), 51-59 0033-3158 108:1-2<51 1992 108 213 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer