While it is likely that the rate of nicotine metabolism influences smoking patterns and the severity of addiction, it may impact differently at different stages (e.g., adolescent versus adult) of smoking. Our results suggest that during adolescence, slower clearance of nicotine may promote rather than impede the development of addiction, perhaps mediated by higher levels of nicotine exposure per cigarette. More studies are needed to confirm these findings. The current findings highlight the importance of studying smokers at various stages of smoking progression.
