Exploring the Severity of Dependence Scale (SDS) as a possible measure of nicotine dependence

ABSTRACT

Background: The time to first cigarette (TTFC) of the day is an emerging single-item indicator of nicotine dependence due to its robust associations with indices of physical dependence. However, it is unclear if this measure adequately captures other dimensions of dependence. The Severity of Dependence Scale (SDS) is a brief questionnaire used to assess psychological aspects of dependence that has not yet been extensively applied to smoking research. Methods: We examined associations between the SDS and TTFC among 255 smokers during the baseline session of a cessation trial. We also examined associations of the SDS and TTFC with biobehavioral dependence indices, quitting behaviors, and cognitive-affective variables and compared the relative contributions of both measures in predicting these variables. Results: TTFC was unrelated to SDS total score, but was related to individual SDS items. TTFC, but not SDS, was correlated with indices of physical dependence (e.g., cigarettes per day [CPD], carbon monoxide [CO]). Both TTFC and SDS were associated with quitting behaviors, with opposite directionality of associations. TTFC and SDS were both associated with cognitive-affective variables, but SDS outperformed TTFC in strength and number of these relationships. Including both the SDS and TTFC as regression model predictors often increased the amount of variance explained. Conclusions: Findings suggest that SDS and TTFC assess different constructs of nicotine dependence; among smokers, the SDS appears to tap into nonphysical components of dependence (e.g., loss of control) that relate to quitting motivation and affect. Assessing nicotine dependence using only the SDS may fail to capture physical dependence and, further, may not reflect the same domains of addiction the SDS assesses in other drugs of abuse. Nonetheless, using 3 SDS items in addition to TTFC may offer utility over using TTFC alone.

KEYWORDS:

• Nicotine dependence
• Severity of Dependence Scale (SDS)
• time to first cigarette (TTFC)

Author contributions

D.C. was the principal investigator on the parent intervention study; he designed and conducted the study, including the collection and management of data. In consultation with J.M.S. and D.C., M.M. conceived the present study, undertook the statistical analyses, interpreted results, and prepared the first draft of the manuscript. J.M.S., S.A.B., and D.C. contributed to data interpretation and the development of subsequent manuscript drafts. All authors reviewed and approved the final manuscript for submission.

Funding

This research was funded by the National Cancer Institute (NCI) grant R01 CA133068; its contents are solely the responsibility of the authors and do not necessarily represent the official views of the National Institutes of Health. NCI played no role in the design of the study, data collection, the writing of the manuscript, or the decision to submit for publication. Varenicline (Chantix) was provided by Pfizer through Investigator Initiated Research Support (no. WS759405). Pfizer reviewed a draft of the manuscript but played no role in the design of the study, data collection, the writing of the manuscript, or the decision to submit for publication. The authors declare that they have no conflicts of interest.