A comparison of the content-, construct- and predictive validity of the cigarette dependence scale and the Fagerström test for nicotine dependence.

BACKGROUND: Research showed that the widely used Fagerstrom test for nicotine dependence (FTND) does not cover important aspects of dependence. A new test, the cigarette dependence scale (CDS-12), covers the main elements in DSM-IV and ICD-10 definitions of dependence. We compared the psychometrics of CDS-12, FTND, and CDS-5 and the heaviness of smoking index (HSI), which are short versions of CDS-12 and FTND, respectively.
METHODS: Internet survey in 2002-2003. Participants were invited one month after answering the first survey to answer a second survey on smoking status and withdrawal symptoms.
RESULTS: Eight hundred two smokers answered both surveys. Cronbach's alpha coefficients were higher for CDS-12 (0.91) and CDS-5 (0.77) than for FTND (0.68) and HSI (0.63). Among 231 smokers who quit smoking at follow-up, higher baseline CDS-12 scores predicted higher withdrawal ratings at follow-up, for all withdrawal symptoms except appetite. FTND and HSI predicted higher craving in quitters, but did not predict the intensity of other withdrawal symptoms. Neither CDS-5, FTND or HSI predicted smoking cessation, but higher CDS-12 scores marginally predicted smoking cessation at follow-up (area under the receiver operating characteristic (ROC) curve = 0.55, 95% confidence interval = 0.51-0.59).
CONCLUSIONS: CDS-12 had better content validity and internal consistency than FTND and was a slightly better predictor of withdrawal symptoms. Unexpectedly, higher (not lower) CDS-12 scores predicted subsequent smoking cessation, perhaps because endorsement of some CDS-12 items implies accepting that one is dependent, which in turn could reflect motivation to quit. CDS-12 may represent an alternative to FTND for measuring cigarette dependence.