Short CommunicationA study of the psychometric properties of the Fagestrom Test for Nicotine Dependence
Introduction
Fagestrom Tolerance Questionnaire (FTQ; Fagestrom, 1978) and its revised form the Fagestrom Test for Nicotine Dependence (FTND; Fagestrom, Heatherthon, & Kozlowski, 1991) are the most widely used measures of nicotine dependence. Items assess smoking rate, smoking soon after waking, smoking even when ill, difficulty refraining from smoking, reporting the first cigarette of the day as the most difficult to give up, smoking more heavily in the morning, nicotine level of cigarette, and frequency of inhalation, the two last items having been removed from the FTND. Most of items are scored on a dichotomous scale. The major criticism of the FTQ and FTND as measures of nicotine dependence mainly include their low internal consistency and their underlying multifactorial structure, suggesting that they did not measure a unidimensional construct of dependence (Colby, Tiffany, Shiffman, & Niaura, 2000). Haddock, Lando, Klesges, Talcott, and Renaud (1999) have recently reported a two-factor structure of the FTND in the largest sample ever tested (7998 young smokers). Only one study, however, used dichotomous data analysis based on tetrachoric correlations, which are the appropriate means of analysis. Radzius, Moolchan, Henningfield, Heishman, and Gallo (2001) performed the first FTQ factorial analysis study utilizing tetrachoric correlations, which also found a two-factor structure. We report the first study of the factorial structure of the FTND in a French population. In this study, we used tetrachoric correlations to assess the internal consistency and the factorial structure of the FTND.
Section snippets
Study sample
The FTND was administered to a sample of 772 adult smokers (420 men, 352 women) (mean age=36.3±9 years, range=17–64 years) recruited in 2000 from the employees supervised by a center for occupational medicine in Toulouse, France.
Analyses
Items 1 and 4 were dichotomized (0 versus other values) and tetrachoric correlation coefficients were computed between the six items. Then, two confirmatory factor analyses were performed. The first analysis tested the two-factor model proposed by Haddock et al. (1999).
Results
Table 1 shows the results of the correlation analysis. All correlation coefficients were significant and higher than .30.
Table 2 (upper and center parts) shows the results of the two confirmatory factor analyses.
The uncorrelated two-factor model did not fit the data very well. The GFI value was much lower than 0.90 and the residual was much higher than 0.10. By contrast, the correlated two-factor model fits the data well. The GFI value was slightly higher than 0.90 and the residual was lower
Discussion
This study of the psychometric properties of the FTND found a monofactorial structure and a high internal consistency achieved by exclusion of Item 3. We propose a revision of the FTND by deleting Item 3 “Which cigarette would you hate most to give up?” These findings suggest that this revised form of the FTND assesses a unidimensional construct and argue for its reliability.
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