GABA Supplementation Negatively Affects Cognitive Flexibility Independent of Tyrosine

Lee Wei Lim, Luca Aquili

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    Increasing evidence, particularly from animal studies, suggests that dopamine and GABA are important modulators of cognitive flexibility. In humans, increasing dopamine synthesis through its precursor tyrosine has been shown to result in performance improvements, but few studies have reported the effects of GABA supplementation in healthy participants. We conducted a double-blind, placebo-controlled, randomized experiment to test the interactive effects of tyrosine and GABA administration on two measures of cognitive flexibility, response inhibition and task switching. A total of 48 healthy volunteers were split into four groups (placebo, tyrosine alone, GABA alone, and tyrosine and GABA combined). They completed cognitive flexibility tasks at baseline and after drug administration. We found that tyrosine alone had no impact on the measures of cognitive flexibility, whereas GABA alone and in combination with tyrosine worsened task switching. Our results provide preliminary evidence that putative increases in GABA and dopamine synthesis do not interact to affect cognitive flexibility performance.
    Original languageEnglish
    Article number1807
    Pages (from-to)1-10
    Number of pages10
    JournalJournal of Clinical Medicine
    Issue number9
    Early online date21 Apr 2021
    Publication statusPublished - 1 May 2021


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