With respect to the biological underpinnings of behavior, we found that genetic variability in CHRM2 accounted for differences in individuals’ probabilities of developing distinct patterns of more general externalizing problems. What, however, are the intermediary mechanisms accounting for this association? Given prior evidence linking CHRM2 to disorders such as alcohol and illicit drug dependence, which are characterized by poor self-regulatory behavior, and to an electrophysiological marker of central nervous system (CNS) hyperexcitability, this gene may be involved in inhibitory control via disturbances in cognition -- information processing in particular. It has been suggested that reduced amplitude of the P300 event-related brain potential, an abnormality which has often been observed in individuals at risk for various forms of externalizing psychopathology, represents either an excess of CNS excitation or a deficit of CNS inhibition. In this way, CHRM2 may play an important role in regulating homeostasis in this neurocognitive system.
