Does hair zinc predict amphetamine improvement of ADD/hyperactivity?

In 18 boys with ADHD (ages 6-12) in a balanced crossover design, parent and teacher hyperactivity rating differences between one month of dextroamphetamine and one month of placebo correlated significantly (p less than .05, 2 tailed) on Pearson's r with baseline hair zinc levels and nonsignificantly with 24-hour urinary zinc excretion. The signs of the correlations were such that a higher baseline zinc predicted a better placebo-controlled response to amphetamine. Patient baseline urinary zinc was significantly (p less than .02) lower than 7 normal controls. These findings are compatible with the possibility that some ADHD children may be mildly deficient in zinc and constitute poorer stimulant responders. Correlations of zinc levels with 24-hour urinary MHPG were in the expected direction but nonsignificantly by 2-tailed test.