Brain activity during a working memory task after daily caffeine intake and caffeine withdrawal: a randomized double-blind placebo-controlled trial.
Level 2 - randomized trial
Individual randomized crossover trial
PubMed 36653409 · doi:10.1038/s41598-022-26808-5
What was done
A double-blind, randomized, crossover trial evaluated working memory in 20 young healthy non-smokers (mean age 26.4 ± 4.0 years; habitual caffeine intake 474.1 ± 107.5 mg/day). Participants completed three 10-day conditions: daily caffeine (150 mg 3 times/day), placebo (3 times/day), and withdrawal (9 days caffeine followed by 1 day placebo). On the 10th day of each condition, participants performed an N-Back working memory task (0-back and 3-back) four times, with task-related BOLD activity measured in the final session via functional magnetic resonance imaging (fMRI).
What was found
No numerical values or effect sizes were reported in the abstract. Compared to placebo, daily caffeine resulted in a higher error rate and longer reaction time in 3-back versus 0-back trials. Caffeine withdrawal also resulted in a higher error rate compared to placebo. Task-related BOLD activity did not differ significantly between conditions, but overall right hippocampal BOLD activity was reduced in the caffeine condition compared to placebo.
Why it matters
This study suggests that habitual daily caffeine intake does not improve working memory and may impair performance while altering hippocampal neurocognitive function relative to a caffeine-free baseline.
Limits
The sample size is very small (n = 20) and restricted to young, healthy non-smokers with high baseline habitual caffeine intake. The abstract reports no numerical values, confidence intervals, or p-values, and interventions lasted only 10 days.
Cited by
- supports Caffeine administration can make individuals feel they are performing better on complex cognitive tasks like the N-back task while they are actually performing worse.