title: Caffeine and theanine exert opposite effects on attention under emotional arousal.
abstract: Tea is perceived as more relaxing than coffee, even though both contain caffeine. L-theanine in tea may account for the difference. Consumed together, caffeine and theanine exert similar cognitive effects to that of caffeine alone, but exert opposite effects on arousal, in that caffeine accentuates and theanine mitigates physiological and felt stress responses. We evaluated whether caffeine and theanine influenced cognition under emotional arousal. Using a double-blind, repeated-measures design, 36 participants received 4 treatments (200 mg caffeine + 0 mg theanine, 0 mg caffeine + 200 mg theanine, 200 mg caffeine + 200 mg theanine, 0 mg caffeine + 0 mg theanine) on separate days. Emotional arousal was induced by highly arousing negative film clips and pictures. Mood, salivary cortisol, and visual attention were evaluated. Caffeine accentuated global processing of visual attention on the hierarchical shape task (p < 0.05), theanine accentuated local processing (p < 0.05), and the combination did not differ from placebo. Caffeine reduced flanker conflict difference scores on the Attention Network Test (p < 0.05), theanine increased difference scores (p < 0.05), and the combination did not differ from placebo. Thus, under emotional arousal, caffeine and theanine exert opposite effects on certain attentional processes, but when consumed together, they counteract the effects of each other.
authors.affiliation: Department of Psychology, Tufts University, Medford, MA 02155, USA.|Department of Psychology, Tufts University, Medford, MA 02155, USA.
authors.forename: Grace E
authors.initials: GE
authors.lastname: Giles
authors.affiliation: Department of Psychology, Tufts University, Medford, MA 02155, USA.|Department of Psychology, Tufts University, Medford, MA 02155, USA.
authors.forename: Caroline R
authors.initials: CR
authors.lastname: Mahoney
authors.affiliation: Department of Psychology, Tufts University, Medford, MA 02155, USA.|Department of Psychology, Tufts University, Medford, MA 02155, USA.
authors.forename: Tad T
authors.initials: TT
authors.lastname: Brunyé
authors.affiliation: Department of Psychology, Tufts University, Medford, MA 02155, USA.|Department of Psychology, Tufts University, Medford, MA 02155, USA.
authors.forename: Holly A
authors.initials: HA
authors.lastname: Taylor
authors.affiliation: Department of Psychology, Tufts University, Medford, MA 02155, USA.|Department of Psychology, Tufts University, Medford, MA 02155, USA.
authors.forename: Robin B
authors.initials: RB
authors.lastname: Kanarek
mesh_terms: D000293:Adolescent; D000339:Affect / Q000187:drug effects; D001143:Arousal; D001288:Attention / Q000187:drug effects*; D002110:Caffeine / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects; D004311:Double-Blind Method; D004347:Drug Interactions; D005260:Female; D005971:Glutamates / Q000494:pharmacology*; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D008297:Male; D012463:Saliva / Q000378:metabolism; D055815:Young Adult
chemical_list: D005971:Glutamates; D002110:Caffeine; C026166:theanine; D006854:Hydrocortisone
keywords: arousal; attention; caffeine; caféine; cognition; cortisol; emotion; fonctions cognitives; theanine; théanine; émotion; éveil