Resting state EEG and genome‐wide genotyping were available for a total of 8,425 individuals from Australia, the Netherlands, and the USA. All subjects were part of twin and family studies examining the genetics of health, neuropsychiatric and behavioral traits with additional psychophysiological assessments: the Minnesota Twin Family Study (MTFS), the Collaborative Study on the Genetics of Alcoholism (COGA), the Brisbane Adolescent Twin Study (BATS), and the Netherlands Twin Register (NTR). All sites excluded subjects with a history of neurological problems, including tumor and head trauma. Alcohol dependence ascertained samples (COGA European Ancestry Families and COGA Case‐Control) required acute alcohol screening prior to EEG recording. Table 1 provides a short summary of each cohort analyzed separately before meta‐analysis.
