Subjects were ascertained and sampled using harmonized protocols from two longitudinal cohort studies, the Netherlands Twin Registry (NTR) 71 and the Netherlands Study of Depression and Anxiety (NESDA). 72 NTR is an observational, 25-year longitudinal study of twins and their families 73–75 The study protocol was approved by Central Ethics Committee on Research Involving Human Subjects of the VU University Medical Center, Amsterdam71. NESDA is a cohort study to investigate the long-term course and consequences of depressive and anxiety disorders and includes persons both with and without emotional disorders72,74,75. The study protocol was approved by the Ethical Review Board of the VU University Medical Centre and subsequently by local review boards of each participating center72. Informed consent was obtained from all participants in both studies.
