A total of 52 children 6- to 14-years old with ADHD were enrolled in a multiphase, double-blind, randomized, placebo-controlled trial investigating zinc supplementation in treating ADHD and optimizing response to psychostimulants. The Swanson, Nolan, and Pelham (SNAP) ADHD rating scale was the primary endpoint. Serum ferritin concentration was obtained at baseline and 8 weeks later. ADHD symptoms were moderately severe at baseline (SNAP item mean=2.1). Mean ferritin concentration was 18.4ng/ ml, with 23% of the participants having a level below 7, the assaydefined threshold for iron deficiency. Serum ferritin was inversely correlated with baseline inattention, hyperactivity/ impulsivity, and total ADHD symptom scores (Partial Spearman’s r=-0.31, p=0.04; r=-0.42, p<0.006; and r=-0.43, p<0.004, respectively) and with the weight-adjusted dose of amphetamine used to optimize clinical response (Partial Spearman’s r=-0.45, p<0.007). These findings add to the growing literature implicating ID in ADHD. The prediction of amphetamine optimal dose by ferritin concentration suggests that iron supplementation should be investigated as a potential intervention to optimize response to psychostimulants at a lower dose in individuals with low iron stores and ADHD. (J Child Adolesc Psychopharmacol. 2010 Dec;20(6):495-502.) PMID: 21186968.
