Full information about each study group is presented in the Supplementary Methods. Individuals were diagnosed according to International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) or Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria. Because of variation in diagnostic criteria and protocols between the various centers, some phenotypic heterogeneity is expected. All individuals provided written, informed consent for participation and approval was obtained from the ethics committees at each location.
