Aspartame, behavior, and cognitive function in children with attention deficit disorder

To determine the effects of large doses of aspartame on behavior, cognition, and monoamine metabolism in children with attention deficit disorder. Design. A randomized, double-blind, placebo-controlled crossover study of unmedicated children meeting Diagnostic and Statistical Manual of Mental Disorders (3rd ed) criteria for attention deficit disorder. Setting. Behavioral assessments were performed in the child's home by their parents and in the classroom by a teacher. Cognitive tests were administered and blood drawing was performed during a 2-day inpatient admission to our Children's Study Center. Interventions. Administration of aspartame (single morning dose, 34 mg/kg) or placebo for alternate 2-week periods. Main outcome measures. Behavioral and cognitive tests included the Matching Familiar Figures Test (MFFT), Children's Checking Task (CCT), the Airplane Test, the Wisconsin Card Sorting Test (WCST), the Subjects Treatment Emergent Symptom Scale (STESS), the Multigrade Inventory for Teachers (MIT), and the Conners Behavior Rating Scale. Blood was drawn for complete blood cell count and liver function tests, as well as amino acid, methanol, formate, serotonin, and monoamine metabolite analyses, and urine was collected for measurement of catecholamine and monoamine metabolite excretion. Results. No clinically significant differences between aspartame and placebo were found for the STESS, MIT, or Conners ratings, or for the MFFT, CCT, WCST, or Airplane cognition tests. Also, no differences were noted for any of the biochemical measures, except for the expected increase in plasma phenylalanine and tyrosine following aspartame. Conclusions. The findings indicate that aspartame at greater than 10 times usual consumption has no effect on the cognitive and behavioral status of children with attention deficit disorder. In addition, aspartame does not appear to affect urinary excretion rates of monoamines and metabolites.