given prior work suggesting that some withdrawal symptoms peak 2–3 days post-cessation57. The limited abstinence period may be why we observed effects for QSU but not MNWS. Although withdrawal symptoms and urges are similar, and often correlated, constructs, they follow different time courses during abstinence; indeed some research suggests that BQSU may have greater sensitivity to early abstinence (24 h) compared to the MNWS.58–60 Real-time behavioral assessments of NicW in abstinent smokers over an extended period could provide important additional insight into the role of rs31746 in NicW. Alternatively, the size of the laboratory sample may have limited the statistical power to detect some effects during early abstinence.
