Table 2.

Values for smoking characteristics by 5-HTTLPR genotype in ever smokers

Characteristic	Mean (SD)		P value
	S/S+S/L	L/L
Duration of smoking	27.4 ± 11.9	26.9 ± 12.7	0.76
No. of cigarettes smoked daily	19.6 ± 10.5	18.2 ± 8.9	0.58
No of pack/years	27.3 ± 20.0	22.4 ± 12.8	0.32
Age of proceeding to regular smoking	19.9 ± 4.5	20.5 ± 5.3	0.76
FTND score*	5.5 ± 2.5	5.3 ± 2.0	0.66
Duration of the longest abstinence in quitting attempts*	368.6 ± 1102.3	211.6 ± 388.2	0.90

*only current daily smokers were analysed