Zinc in the therapy of the attention-deficit/hyperactivity disorder in children. A preliminar randomized controlled trial

The attention-deficit/hyperactivity disorder (ADHD) is a neurological/behavioral disorder which begins in childhood. Zinc has a potential role as an adjuvant therapy for ADHD. The objective was to evaluate the effect ofZn supplementation on behavior, as a complementary therapy to metylphenidate, in pediatrics patients with ADHD. In a controlled, double blind design, 40 patients with clinical criteria ofADHD (DSM-IV) and psychometric evaluation (WISC-R), were selected (31 boys and 9 girls, 7-14 years of age). They were randomized to receive methylphenidate 0.3 mg/kg/d + placebo (sucrose) (group placebo, GPL) or methylphenidate 0.3 mg/kg/d + zinc (sulfate) 10 mg/d (group Zn, GZN) for 6 weeks. A blood sample was drawn at time 0 and 6 weeks, for plasma Zn analysis. The teacher and parent ADHD rating scale (Conners' global index, CGI) was applied at both times. Among the results, plasma Zn was normal at time 0, decreasing especially in the GPL after 6 weeks (GPL: 95.9 +/- 21.5 to 77.9 +/- 15.5; GZN: 90.3 +/- 9.1 to 85.0 +/- 12.0 microg/dL; NS). The CGI by teachers showed a non-significant improvement with Zn: GPL: 18 (9-28) to 16 points (2-26); GZN: 19 (6-24) to 11 points (3-23) (p = 0.07); no significant difference in the CGI by parents by groups was found: GPL: 19 (7-25) to 13 (3-22); GZN: 19(7-25) to 11(2-19). We conclude that a decrease in plasma Zn levels in both groups was found, greater in the placebo group. An apparent improvement in ADHD signs in children was observed with the Zn supplementation, according to the Conners global index by teachers.