It starts with nicotine. C10H14N2. Ten carbon atoms, 14 hydrogens, and two nitrogens in each molecule.

When consumed by humans through smoking, nicotine is taken up by receptors in the brain, stimulating the release of dopamine, a chemical messenger that elicits feelings of happiness. When working properly, it stimulates and rewards actions that are beneficial to the body. Addiction is a behavioural response to that rush.

Every story of addiction is personal and unique, held together by the threads of dependence. That’s no different for Nova Scotia’s Shelley Caffatos and PEI’s Kim Asling-Ings, who struggled to quit smoking.