If you get angry easily, you may have a genetic profile that also makes you especially susceptible to nicotine addiction, according to researchers at the University of California at Irvine.

The scientists made the discovery while studying people who wore nicotine patches, the Associated Press reports. Brain scans revealed that nicotine triggered bursts in certain brain activity, but only in people prone to becoming easily angered.

Psychiatrist Steven Potkin, who led the study, says the findings could explain why some people are more prone to start smoking than others, and why the same people might find it harder to quit.

Moreover, he says, teenagers are generally more prone to fits of aggression since parts of their brains that control impulse are still forming. This may explain why people who begin smoking generally do so while in their teens.

Despite the common notion that nicotine has a calming effect, it may actually make smokers with "type A" personalities even more aggressive, Potkin tells the wire service. "They may smoke to feel better, but they don't," he points out.