The NIMH-CPES sample was based on a multistage clus- tered area probability sample of the US population. The sample consisted of 20,013 American citizens. The mean age of the sample was 43.38. The sample was representa- tive of the US population and also racially and ethnically diverse. Therefore, the results of these findings include different racial and ethnic backgrounds which most pre- vious research has failed to consider. Further informa- tion on the sample designs can be found in Heeringa et al. (2004). Please refer to Table 1 for the main features of the sample designs of the Collaborative Psychiatric Epidemiology Studies.