Dosages of Nutrient Supplements and Potential Long-Term Toxicity in Attention-Deficit/Hyperactivity Disorder Micronutrient Study.

We read with interest the article by Johnstone et al.1 reporting their vitamin-mineral randomized trial that found that children with attention-deficit/hyperactivity disorder (ADHD) showed global benefit over placebo by blinded clinician rating, but not by parent-report CASI-5 composite rating in a population with ADHD and irritability. Because some of the mineral dosing was in potentially toxic ranges, we sought to examine the trial findings. Given that the producing company is promoting their supplement for long-term use,2 the scientific and consumer communities might value some additional information about potential toxicity from long-term dosing.