Abstract/Summary

Background: Sensory reactivity differences are experienced by between 5 and 15% of the population, often taking the form of sensory over-responsivity (SOR), in which sensory stimuli are experienced as unusually intense and everyday function is affected. A potential mechanism underlying over-responsivity is an imbalance between neural excitation and inhibition in which inhibitory influences are relatively weakened. Therefore, interventions that boost neural inhibition or reduce neural excitation may reduce SOR; Vitamin-B6 is the coenzyme for conversion of excitatory glutamate to inhibitory GABA, and in animal models it both increases the concentration of GABA and reduces glutamate. Aims: To discover whether taking a high-dose of Vitamin-B6 reduces SOR and other aspects of sensory reactivity. Methods: We recruited 300 adults (249 females) from the general population who completed the Sensory Processing 3-Dimensions Scale (SP-3D) first at baseline, and again following randomisation to either one month’s supplementation with 100 mg Vitamin-B6, or one of two control conditions (1000 µg Vitamin-B12 or placebo). To focus on individuals who experience sensory over-responsivity, we analysed the effects of supplementation only on individuals with high baseline SOR scores (above the 87th percentile). Results: In individuals with sensory over-responsivity at baseline, Vitamin-B6 selectively reduced SOR compared to both placebo and Vitamin-B12. We also found that Vitamin-B6 selectively reduced postural disorder in individuals with high scores on this subscale at baseline, but there were no effects on the four remaining SP-3D subscales. Conclusions: Clinical trials and mechanistic studies should now be conducted in autism, ADHD, and other groups with SOR.