title: Trait-anger enhances effects of caffeine on psychomotor vigilance performance.
abstract: This study examined the combined effects of caffeine and the personality attribute of trait-anger on the speed of psychomotor vigilance performance during sleep deprivation. 23 young adult soldiers (19 male) were administered the State-Trait Anger Expression Inventory-2 when well-rested. Participants were then sleep deprived for three consecutive nights (77 hours total) during which they completed repeated psychomotor vigilance testing. Half of the participants received four doses of oral caffeine (200 mg every 2 hr.; 800 mg total) each night, while the other half were administered a placebo. For the first night, higher scores on trait-anger, outward anger expression, and intensity of anger expression predicted better sustained overnight vigilance performance, but only for those volunteers receiving caffeine. These correlations were not significant for the subsequent nights. Findings suggest a possible synergistic effect between personality traits associated with arousal of the central nervous system and vigilance-promoting effects of caffeine.
authors.affiliation: Department of Behavioral Biology, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA. william.killgore@na.amedd.army.mil
authors.forename: William D S
authors.initials: WD
authors.lastname: Killgore
authors.forename: Desiree B
authors.initials: DB
authors.lastname: Killgore
authors.forename: Goutham
authors.initials: G
authors.lastname: Ganesan
authors.forename: Alexandra L
authors.initials: AL
authors.lastname: Krugler
authors.forename: Gary H
authors.initials: GH
authors.lastname: Kamimori
mesh_terms: D000328:Adult; D000786:Anger; D001143:Arousal / Q000187:drug effects*; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D010551:Personality; D011597:Psychomotor Performance / Q000187:drug effects*; D011795:Surveys and Questionnaires
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine