A factor analysis of the Fagerström Test for Nicotine Dependence (FTND).

Psychometric study of the Fagerström Test for Nicotine Dependence (FTND) provides insight into its structure and the dimensions of nicotine addiction it assesses. We evaluated the factor structure of the FTND in 541 research volunteers, most with histories of polysubstance use. Tetrachoric and phi correlation techniques were utilized and promax- and varimax-rotated solutions are reported. Two factors were found. Factor 1 was defined by questions regarding time to first cigarette in after waking, which cigarette is most preferred, and prominence of morning smoking. Factor 2 was defined by questions regarding difficulty refraining from smoking, amount smoked, and smoking while ill. The question "How soon on waking do you smoke your first cigarette?" loaded substantially on both Factor 2 and Factor 1. Repeating the analyses after stratification by gender did not change the results. The factor structure from our sample population was similar to results reported by previous studies with different types of populations. We propose that Factor 1 assesses the degree of urgency to restore nicotine levels to a given threshold after nighttime abstinence, whereas Factor 2 reflects the persistence with which nicotine levels are maintained at about that threshold during waking hours. Thus, the FTND may assess distinguishable self-reportable pharmacological dimensions of nicotine addiction. These two dimensions may provide indirect assessment of a smoker's daily nicotine intake. Testing this hypothesis requires correlation of biomarkers and responses to specific items of the FTND.