Psychoeducational and impulsivity correlates of platelet MAO in normal children.

The authors examined the relationship between the activity of platelet monoamine oxidase (MAO) and a variety of psychoeducational measures, as well as the scores on the Matching Familiar Figures Test (MFF), a psychological test of reflection-impulsivity, in 21 normal children (12 boys, 9 girls) who were admitted to a clinical research center and placed on a low monoamine diet. The children were divided into three equal groups (n = 7) based on their values of platelet MAO. There were no significant differences among the three groups in the psychoeducational measures. However, the high and low MAO groups made significantly more errors and had shorter latency periods on the MFF than the middle MAO group. These findings suggest that normal children with platelet MAO activity values in the high and low ends of the MAO distribution are more impulsive than the children with platelet MAO values in the middle range on the MFF Test of Impulsivity. The findings further suggest that there is no relationship between platelet MAO levels and intellectual abilities or scholastic achievement in normal children.