Heritability of the total cortical thickness was less in 6 and 8 years old children (65–71%)(Yoon et al. 2010; van Soelen et al. 2012b; van Soelen et al. 2013) than that in 12 and 14 years old adolescents (80–81%)(van Soelen et al. 2012b; Yang et al. 2012; van Soelen et al. 2013) or in mid-aged adults (81%)(Panizzon et al. 2009). In 8 year old children, overall cortical thickness in the frontal, temporal, parietal and occipital lobes exhibited moderate to high heritability (53–72%), whereas regional thickness of the lobules in the inferior and superior parietal and inferior temporal cortices showed low heritability (<30%)(Yoon et al. 2010). In adolescents, the thickness of the prefrontal cortex, including bilateral dorsolateral and superior frontal regions, and the middle temporal and supramarginal cortices, had heritability greater than 75% (Schmitt et al. 2009; Lenroot et al. 2009; Yang et al. 2012). As in adults (Tramo et al. 1998; Joshi et al. 2011), differences in heritability were observed between hemispheres in adolescents in multiple frontal regions (Schmitt et al., 2009; Yang et al. 2012). In 9 and 12
