Effect of tyrosine on attention deficit disorder with hyperactivity.

A single-blind study was conducted to evaluate the effect of oral tyrosine on attention deficit disorder (ADD) with hyperactivity in seven outpatient children. Since most biological evidence of ADD supports a norepinephrine or dopamine deficiency, the authors hypothesized that tyrosine, which has been shown to increase catecholamine synthesis, would be beneficial in the treatment of ADD. None of the subjects, however, showed any significant improvement with tyrosine. Implications for the catecholamine deficiency hypothesis and treatment strategies for ADD are discussed.