Because conduct problems, smoking, and obesity overlap, and affect brain function, a relevant question is: are the effects independent or interactive? In the case of smoking, the answer is “independent”. Smoking was not associated with the same changes in P300 latency, or in anterior scalp P300 amplitude, found in the analyses of conduct problems and obesity. In addition, it did not statistically interact with the other factors. Smoking was only associated with a reduction in P300 amplitude over the posterior scalp (Table 2).
