Our study has some limitations. Firstly, we lacked behavioral measures that selectively target performance in executive function and working memory domains that others have found to vary by Val158Met genotype(Barnett et al., 2007). Secondly, we did not have a sufficient sample size to examine differences between HCs, COS probands and SIBs in how allelic variation at Val158Met interacts with other genetic variants of potential relevance for dopaminergic systems both within (Meyer-Lindenberg et al., 2006), and beyond [e.g. DRD2, (Fazio et al., 2011)] the COMT gene—although we hope to address these issues in the future using larger samples. Thirdly, although (based on earlier developmental studies) we modeled CT change with age in a linear manner, it is conceivable that genetic influences in CT change may be non-linear in nature. Larger longitudinal datasets than ours will be required to more formally test for the presence of these more complex, and as yet hypothetic genotypic effects on structural maturation. Finally, our approach to image analysis focused in CT and different methods will be required to determine how Val158Met genotype modulates other aspects of
