Nicotine: evolution, dependence, and the path to total quit: redefining cessation in a changing nicotine landscape

The nicotine marketplace has expanded beyond combustible cigarettes to include electronic nicotine delivery systems (ENDS), heated tobacco products (HTPs), nicotine pouches, and licensed medicinal nicotine products. This diversification has altered patterns of exposure, dependence, and cessation, while complicating the meaning of "quitting" in public health and clinical practice.

To review the evolving evidence on nicotine dependence across product categories and to examine whether smoking cessation alone remains an adequate endpoint in a landscape where nicotine use may persist beyond combustible tobacco.

This narrative review synthesises evidence from neurobiology, epidemiology, clinical cessation research, and public health literature. Priority was given to systematic reviews, meta-analyses, clinical guidelines, and population-level data relevant to nicotine dependence, product risk, and cessation pathways.

Nicotine dependence is shaped by pharmacology, delivery kinetics, behavioural conditioning, and product design. While non-combustible nicotine products may reduce exposure to smoking-related toxicants for people who switch completely from smoking, they may also sustain nicotine dependence, support dual use, and create new pathways to initiation among individuals who might otherwise have remained nicotine-free. Current cessation frameworks often focus on smoking abstinence without fully addressing continued nicotine dependence, particularly among long-term users of ENDS, HTPs, nicotine pouches, and other non-combustible products.

In a changing nicotine landscape, cessation frameworks should distinguish more clearly between smoking cessation and nicotine cessation, support users across all nicotine product types, and re-establish complete freedom from nicotine dependence (Total Quit) as the optimal endpoint where achievable.