“…Subcortical regions that are abnormal in adults with ADHD include the caudate (Almeida et al, 2010; Almeida Montes et al, 2010; Onnink et al, 2014; Proal et al, 2011; Seidman et al, 2011), amygdala (Frodl et al, 2010), hippocampus in medicated individuals (Onnink et al, 2014), nucleus accumbens (Seidman et al, 2006), and cerebellum (Biederman et al, 2008). Therefore, studies in adults with persistent ADHD have found brain structural abnormalities that are also seen in childhood (Castellanos et al, 2003; Castellanos and Proal, 2012; Cherkasova and Hechtman, 2009; Frodl and Skokaukas, 2012; Pastura et al, 2011; Peng et al, 2013). However, it is notable that most of these studies included samples that were, on average, older than twenty-five years of age (Ahrendts et al, 2011; Almeida et al, 2010; Almeida Montes et al, 2010; Amico et al, 2011; Biederman et al, 2008; Clerkin et al, 2013; Frodl et al, 2010; Hesslinger et al, 2002; Makris et al, 2007; Mattfeld et al, 2014; Onnink et al, 2014; Perlov et al, 2008; Seidman et al, 2011, 2006; Almeida Montes et al, 2013) when most gray matter neuromaturation is complete (e.g., Giedd et al, 1999) and in older samples, gray matter may be reducing due to aging.…”