Mental Health | Vitamin D supplementation resulted in a small but statistically significant improvement to ADHD symptoms.
A recent systematic review and meta-analysis assessed the benefits and harms of vitamin D supplementation in patients with attention-deficit/hyperactivity disorder (ADHD).
To investigate these outcomes, study authors searched various clinical databases for randomized controlled trials (RCTs) where vitamin D supplementation was used alone or as an adjunctive therapy in ADHD patients.
Based on their inclusion criteria, the authors identified 4 RCTs involving 256 children with ADHD being treated with methylphenidate and concomitant vitamin D. These studies, which ranged from 6 to 12 weeks in duration, utilized doses of vitamin D between 1000 IU/day and 50,000 IU/week.
“We found that vitamin D supplementation may alleviate ADHD symptoms, which were supported by improvements in ADHD total scores, inattention scores, hyperactivity scores, and behavior scores,” the authors stated. However, they added, statistically significant improvements in oppositional measures were not observed. 
With regard to safety, findings from the analysis showed no significant differences in adverse events between vitamin D and placebo; supplementation with vitamin D also resulted in increased vitamin D levels in these patients.
Based on their findings, the authors concluded that vitamin D supplementation, as an adjunct to methylphenidate, may benefit patients with ADHD, however evidence for this effect was found to be of low quality. “Future studies should consider baseline vitamin D levels and address different dosing (low or high dose) and the frequency of vitamin D supplementation,” they added.
