New research published in Experimental and Clinical Psychopharmacology has found that caffeine can help adolescents pay attention for longer periods of time. Though it is commonly assumed that caffeine enhances vigilance in such a manner, until now experimental evidence had been lacking or inconclusive.
“I have often used caffeine, particularly coffee or energy gum, to keep alertness during long class periods, meetings, and car drives, and many of my colleagues and friends also use caffeine to remain mentally sharp,” said study author Robert Cooper, a PhD candidate at the University at Buffalo.
“After reviewing the literature on caffeine and sustained attention, the evidence was surprisingly equivocal, despite most of us believing caffeine can positively influence our ability to perform during periods where prolonged attention is required. It also became clear that much of this literature did not focus on adolescents, which is a critical development period where caffeine use may escalate.”
In the double-blind study, which included three testing sessions, 31 adolescents consumed either 1 mg/kg or 3 mg/kg of caffeine or a placebo before they completed a sustained attention task. The task required the participants to monitor a monotonous stream of four-digit numbers in order to detect rare identical pairs for about 30 minutes. The participants were asked to abstain from caffeine for 24 hours before each testing session.
Performance during the early stage of the attention task was similar across all three doses, and performance tended to decline over time. But the researchers found that performance among participants who received caffeine declined less as time dragged on compared to placebo.
“Among a population of adolescents who use relatively modest amounts of caffeine, acute caffeine maintained their ability to remain alert during a long, monotonous task, which parallels a long class period. There was also some marginal evidence suggesting that larger doses of caffeine may be more effective than smaller doses at maintaining sustained attention,” Cooper told PsyPost.
“Caffeine’s influence on attention is not apparent until about 10 minutes into a sustained attention task. That is, caffeine did not improve performance from the beginning of the task, but helped maintain attention, reducing the dropoff in performance that occurs over time in the absence of caffeine.”
Those 10 minutes may explain why some previous research — which used shorter attention tasks — did not find conclusive evidence that caffeine enhanced vigilance.
But like all research, the new study includes some limitations.
“This study does not directly study the impact of chronic use of caffeine. Chronic use of caffeine may lead to tolerance and loss of cognitive benefits. Chronic use may create sleep disruptions, creating a feedforward cycle of caffeine use and sleep deprivation,” Cooper explained.
“While we found preliminary evidence suggesting caffeine is even more effective for maintaining vigilance for adolescents who have daytime sleepiness, more longitudinal studies are needed to understand the complex relationships between caffeine, cognition, and sleep.”
“Caffeine is the most widely used psychoactive drug in the world, so it is important to understand its influence on human behavior and cognition. More research using caffeine can help us understand why a majority of the population, adolescents included, use (or rely on…?) caffeine on a daily basis, especially now that highly caffeinated energy drinks and caffeine alternatives (such as energy gum and chocolate!) are widely available,” Cooper added.
The study, “Caffeine Enhances Sustained Attention Among Adolescents“, was authored by Robert K. Cooper Jr., Schuyler C. Lawson, Sarah S. Tonkin, Amanda M. Ziegler, Jennifer L. Temple, Larry W. Hawk Jr.