Two other issues are considered: (1) breadth of the TD construct, because too narrow a focus may boost some indices (e.g., internal consistency), but may reduce overall utility [49, 50], and (2) “difficulty” of an item or criteria. An “easy” item or scale (one that is “passed” by many individuals) may be sensitive to low levels of the construct, but may lack both specificity and discrimination at higher levels of dependence. An item that is too “hard” may set the bar too high and miss detection of meaningful levels of dependence (i.e., good specificity but low sensitivity). The “difficulty level” of the DSM, and its possible implications for sensitivity and specificity, is a vital question. The field has not achieved consensus on the proper “difficulty level” for optimal TD diagnosis [51]. Since virtually all regular or daily smokers find it difficult to quit, experience withdrawal, and face huge personal costs from smoking, one could argue that almost all smokers should be diagnosed as dependent (see [10]) for related concerns); however, only about half of daily smokers meet DSM diagnoses for
