P300 and the Stroop Effect in Overweight Minority Adolescents

AIM: The goal was to examine the relationship between a risk factor for poor cognitive control and a health outcome of growing public significance--an excess body mass--among adolescents. METHODS: To this end, 109 adolescents aged 14-20 years were recruited and assigned to 1 of 4 groups defined by the crossing of the absence versus presence of a parental history (PH) of externalizing disorders with a body mass index (BMI) percentile (BMIP) < 85 versus > or = 85. The principal measure estimating cognitive control was the P300 event-related electroencephalographic response recorded during the Stroop task. RESULTS: The analyses revealed a synergistic interaction between BMIP rank, PH and trial type: the increase in P300 latency and the decrease in response accuracy, elicited by the presence of interfering information, were markedly greater in high-BMIP subjects with a PH of externalizing disorders than in the other subject groups. Analyses of a later component, the N450, previously associated with the Stroop interference effect, revealed no effect of BMI or PH. CONCLUSIONS: We conclude that subjects with both a PH of externalizing disorders and an excess BMI constitute a unique group that is less able to resolve cognitive conflict than others. The excessive delay in P300 evoked by conflicting response demands in these subjects may be a marker of a heritable factor that increases risk for both excess body mass and substance use disorders.