Dimensionality of DSM-IV nicotine dependence in a national sample: an item response theory application.

BACKGROUND: Research focusing on the development of a dimensional representation of DSM-IV nicotine dependence is scarce and prior research has not assessed the role of nicotine use criteria in that a dimensional representation, nor the invariance of the DSM-IV nicotine dependence criteria across important population subgroups.
METHODS: Using a large, representative sample of the U.S. population, this study utilized item response theory (IRT) analyses to explore the dimensionality of DSM-IV nicotine dependence criteria and several candidate criteria for cigarette use among past-year cigarette smokers (n=10,163).
RESULTS: Factor analyses demonstrated the unidimensionality of nicotine dependence criteria and IRT analyses demonstrated good fit of the observed responses and the underlying, unobserved latent trait of dependence severity. The model containing all seven DSM-IV dependence criteria, along with the consumption criterion of smoking at least a quarter of a pack of cigarettes in a day in the past year, was identified as the best-fitting model. No differential criterion functioning was shown across sex, race-ethnicity, and age subgroups. DISCUSSION: Major implications of this study are discussed in terms of the addition of a dimensional representation of nicotine dependence to pre-existing categorical representations of the disorder in the DSM-V, and the need for a nicotine consumption criterion to improve representations of nicotine dependence severity. Copyright 2009. Published by Elsevier Ireland Ltd.