CPA subjects in these future studies as well. In any case, the subgroup that was available for the DNA methylation analysis did not differ in its basic behavioral and socioeconomic characteristics from the original group (Table 3). Third, although we ruled out several of the most common confounders, there are some confounders that are tightly correlated with aggression. Cytokine levels as well as DNA methylation were previously associated with psychiatric diseases such as major depression [94], nevertheless the CPA and control groups were not significantly different in levels of anxiety and presence of psychiatric diagnoses as well as age. However, the CPA and control groups were significantly different with respect to variables that are also known to be strongly associated with chronic physical aggression trajectories from childhood to adolescence: childhood hyperactivity and opposition and adulthood criminal behavior [6], [11]. Thus, it is impossible to determine whether the differential DNA methylated regions that we identified associate with aggressiveness or hyperactivity and criminal behavior. This however might be reflecting the simple fact that these behaviors are molecularly and functionally linked within the same biological pathways.
