University of Missouri researchers say quitting smoking can have long-term personality benefits, not just long-term health benefits. Andrew Littlefield, a doctorial candidate working on the study, says it followed participants for 17 years, studying them in age groups.

He says those who started smoking young and quit by the time they were 25 showed the greatest decrease in impulsivity and neuroticism. Impulsivity is the tendency to act without thinking it through, and neuroticism is worrying or being nervous.

Littlefield says after a person turns 35, it has less of an effect, meaning that smoking is more compulsive than impulsive.

The study was conducted by questionnaires every few years with questions that asked participants how much or little a statement described them. Littlefield says, from this, the researchers were able to get a better picture of how quitting smoking has long-term effects on personality.