Table 1.

Evaluation of physical dependence

Methods	Diagnostic thresholds
Fagerström questionnaire: 0–2: no dependence 3–4: low dependence 5–6: moderate dependence 7–8: high dependence 9–10: very high dependence	1. How soon after you wake up do you smoke your first cigarette? (0) >60 min; (1) 31–60 min; (2) 6–30 min; (3) ≤5min 2. Do you find it difficult to refrain from smoking in places where it is forbidden? (0) No; (1) Yes 3. Which cigarette would you hate most to give up? (1) The first in the morning; (0) Any other 4. How many cigarettes per day do you smoke? (0) ≤10; (1) 11–20; (2) 21–30; (3) >30 5. Do you smoke more frequently during the first hours after awakening than during the rest of the day? (0) No; (1) Yes 6. Do you smoke even if you are so ill that you are in bed most of the day? (0) No; (1) Yes
Exhaled CO	0–5 p.p.m.: Non-smoker (at least for 24 h) 5–10 p.p.m.: Light exposure, >6 h from the last cigarette, passive smoking or exposure to other environmental CO >10 p.p.m.: current smoker
Carboxyhaemoglobin	>1.7% in the blood: active smoker
Urinary cotinine	Inhaled nicotine (mg/24 h) = 0.013× urinary cotinine (µg/L) <10µg/L: non-smoker and <50µg/L: passive smoker