Regarding theta power, the present results are not consistent with those of previous studies, which found increased theta power in the BD group compared with the non-BD group (Correas et al., 2015; López-Caneda et al., 2017). Theta band activity decreases as gray matter volume decreases (Squeglia et al., 2012; Howell et al., 2013; Doallo et al., 2014; Correas et al., 2015), and gray matter volume decreases gradually during normal development (Lenroot and Giedd, 2006; Fuhrmann et al., 2015). Therefore, the increased theta power in binge drinkers observed in previous studies implies delayed gray matter development in binge drinkers (Correas et al., 2015). The inconsistent findings between this and previous studies in terms of theta power may be related to participant characteristics such as age. That is, the average age and age of alcohol consumption onset of participants in previous studies were 18 and 14 years, respectively (Correas et al., 2015; López-Caneda et al., 2017), whereas those in this study were 21 and 18 years, respectively. Given that childhood drinking affects brain development, including gray matter development (Stiles and Jernigan, 2010),
