of control families was ascertained to provide normative measures; they were not screened to eliminate those with psychiatric disorders, and are similar to a general population sample. Written informed consent was obtained from all subjects, and the Institutional Review Boards (IRB) of each collaborative site approved all procedures. A more complete description of the recruitment procedures can be found in Begleiter et al. [1,22]. Over 13,000 individuals have been interviewed to date.
