Addiction risk varies with tiny 'hits' of nicotine

A study has explored never-smokers' vulnerability to nicotine addiction.

In a study with 18 adults who had never smoked, scientists at Johns Hopkins report they have demonstrated one of the earliest steps, nicotine "reinforcement," in the process of addiction, and shown that some people are far more vulnerable to nicotine addiction than others.

In a summary of the research, the investigators say they have for the first time, characterized the body's reaction to the first, tiniest "hits" of nicotine. The results, they say, should lay groundwork for future revelations about genetic or other biological factors that make people vulnerable to nicotine addiction.

Addiction researcher Roland R. Griffiths said that results suggest there are definitely some people who are nicotine avoiders and others who are nicotine choosers and there are probably genetic or metabolic vulnerabilities that make people fall into one group or the other.

Griffiths notes that scientists have struggled for decades to understand why, in the face of initial dislike, so many become addicted to cigarettes and so, he and his team set out to explore the conditions under which nicotine's reinforcement properties first take hold in never-smokers.

Griffiths believes this is the first study to conclusively show that nicotine can pass the reinforcement test in never-users, and he expects it will inform future studies of "avoiders" and "choosers."

Ultimately, he says that he hopes findings will point the way toward future interventions that prevent or treat nicotine addiction, a topic of increasing importance in light of the expanding marketing of electronic nicotine delivery devices -- e-cigarettes -- to youthful nicotine nonusers.

The study is published online in the journal Psychopharmacology.