People who tend to be angry are more susceptible to nicotine's effects, hence more likely to become addicted to cigarettes, according to the latest study.
Jean Gehricke led a team of researchers from the University of California (U-C) which studied the effect of nicotine patches on the subjects' tendency to retaliate in response to anger provocation.
The subjects played a computer game and could see a video screen of another player who they believed to be their opponent, although, in fact, they were playing alone.
After each round, the victor could give his opponent a burst of unpleasant noise - at a duration and volume set by the winner.
In some of the subjects, nicotine was associated with a reduced tendency to retaliate, even after provocation by the 'opponent', according to a U-C release.
"Participants who showed nicotine-induced changes in anger task performance also showed changes in brain metabolism. Nicotine-induced reductions in length of retaliation were associated with changes in brain metabolism in response to nicotine in brain areas responsible for orienting, planning and processing of emotional stimuli," said Gehricke.