Chunk #32 — Suggested Criteria for the Assessment of Tobacco Dependence — Rationale for Included Criteria — Criteria 3 & 4: Time to first cigarette (TTFC) after waking, and usual number of cigarettes consumed per day (cpd)
Research by Heatherton and his colleagues [23] found that amongst FTND items, 1 & 4 (TTFC & CPD) were particularly predictive of effective dose biomarkers (e.g., carbon monoxide, blood/urine nicotine, and cotinine levels) and labeled these items the Heaviness of Smoking Index (HSI: [8]). These findings agree with earlier positive findings on similar items [102–105]. Subsequent research has generally supported the conclusion that the two HSI items account for much of the discriminative and predictive validity of the FTND with regard to both effective dose biomarkers and cessation likelihood [22, 106]. The two HSI items are also being used for assignment of dosage of nicotine replacement treatment [107]; see [108]. Finally, the two items are strongly correlated but can yield additive predictive validity (cf. [22, 28, 35, 95]), suggesting that both items be retained to provide meaningful coverage of this important domain.
