Chunk #17 — RESULTS — Genetically informative research approaches and their limitations — The relationship between genetics of use and genetics of abuse/dependence?
These shared environmental factors appear to be less prominent in the transitions for smoking initiation/regular smoking to nicotine dependence, with correlated genetic vulnerabilities serving as the primary source of covariation across these stages of smoking. In an adult sample, 60 -74% % of the liability to nicotine dependence was shared with earlier stages of smoking33,43. In contrast, Heath et al44 reported minimal overlap between genetic influences on persistent smoking and those on initiation, leading to speculation that the etiology of persistent smoking (i.e. inability to quit) may be distinct from nicotine dependence.
