Our study was motivated by epidemiological and clinical data supporting nosological distinctions between FTND and ICD or DSM-based diagnoses, including some studies that suggest qualitative and quantitative differences in associations between DSM- and FTND-defined nicotine dependence and some psychopathology8,9. The FTND is brief, and thus easily and frequently collected. It has been especially prioritized in clinical trials of tobacco cessation10,11, likely because FTND scores correlate well with relapse and treatment response and the scale places a great deal of emphasis on physiological aspects of dependence (e.g., items related to tolerance and withdrawal12). On the other hand, both ICD- and DSM-based nicotine dependence include criteria related to physical and psychological (and social, in DSM-5) impairment due to nicotine/tobacco use, as well as behaviors directed at seeking and using nicotine to the exclusion of other activities. Neither FTND nor the ICD-TUD diagnostic classification maps perfectly to DSM-NicDep13,14.
