first cigarette was solely associated with FTND. Taken together, these item-level analyses suggest that the DSM-NicDep GWAS may have indexed genetic liability to a distinct set of tobacco-related problems than the FTND GWAS. However, many confidence intervals on these estimates were wide. Future item-level GWAS using novel structural equation modeling methods that bring together DSM and FTND items might be of high value at parsing whether genetic and clinical heterogeneity align (Figure 3).
