Additional Contributions: Biomaterials and phenotypic data were obtained from the following projects that participated in the NIMH “control” samples: control subjects from the NIMH Schizophrenia Genetics Initiative and data and biomaterials collected by the Molecular Genetics of Schizophrenia II collaboration. The investigators and coinvestigators are as follows: Evanston Northwestern Healthcare/Northwestern University (grant MH059571), Pablo V. Gejman, MD (collaboration coordinator and principal investigator), Alan R. Sanders, MD; Emory University School of Medicine (grant MH59587), Farooq Amin, MD (principal investigator); Louisiana State University Health Sciences Center (grant MH067257), Nancy Buccola, APRN, BC, MSN (principal investigator); University of California–Irvine (grant MH60870), William Byerley, MD (principal investigator); Washington University (grant U01, MH060879), C. Robert Cloninger, MD (principal investigator); University of Iowa (grant MH59566), Raymond Crowe, MD (principal investigator), Donald Black, MD; University of Colorado (grant MH059565), Robert Freedman, MD (principal investigator); University of Pennsylvania (grant MH061675), Douglas Levinson, MD (principal investigator); University of Queensland (grant MH059588), Bryan Mowry, MD (principal investigator); and Mt Sinai School of Medicine (grant MH59586), Jeremy Silverman, PhD (principal investigator). The samples were collected by V. L. Nimgaonkar's group at the University of Pittsburgh as part of a multi-institutional collaborative research project with Jordan Smoller, MD, DSc, and Pamela Sklar, MD, PhD (Massachusetts General Hospital) (grant MH 63420). Genotype data were generated at the Center for Genotyping and Analysis at the Broad Institute of Harvard and MIT as part of a multi-institutional collaborative research study (principal investigator: Pamela Sklar, MD, PhD; Jordan Smoller, MD, ScD; Vishwajit Nimgaonkar, MD, PhD; and Edward Scolnick, MD). We thank all the coworkers at the Department of Psychiatry, Ludwig-Maximilians-University, Munich, for their excellent contribution to the characterization of the participants and the laboratory work. MALDI-TOF genotyping of the replication sample was conducted at the Genetics Research Centre GmbH, which is a joint initiative between GlaxoSmithKline and the Department of Psychiatry, Ludwig-Maximilians-University. Mike Neale, PhD, and Steve Aggen, PhD, contributed to the development of the Mx code for taking measurement invariance into account. Most important, we thank the individuals who have participated in and contributed to these studies.