Zinc for treating of children and adolescents with attention-deficit hyperactivity disorder : a systematic review of randomized controlled clinical trials

This study systematically reviews the randomized clinical trials examining the effect of zinc on attention-deficit hyperactivity disorder (ADHD), searching the PubMed/Medline and Scholar Google databases. All randomized controlled trials that examined zinc as the intervention, and ADHD as the primary outcome were included. Only three randomized controlled trials, one which included a community sample and two that included clinical samples, met inclusion criteria. The only trial that was well controlled and randomized according to the baseline zinc level showed that using zinc, either alone or in combination with stimulants, did not improve ADHD. Considering the lack of clear evidence for the effect of zinc on ADHD and the possible effect of zinc on the nervous system, more clinical studies are needed to prove or disprove the effect of zinc as a monotherapy or adjuvant therapy.