The study results show both males and females who were pathologically reckless and impetuous attracted more short-term partners than participants with average personalities. And obsessive-compulsive males—but not females—were successful at securing long-lasting mates, an outcome strongly associated with this group’s high income (obsessive-compulsives made nearly twice as much as the less obsessive study participants), Gutiérrez says.

The study results also revealed that neurotic females were more likely to be in lasting relationships. The most neurotic female participants had 34 percent more long-term mates and 73 percent more children than average despite exhibiting a trait typically associated with instability, anxiousness and insecurity, he explains.

According to Gutiérrez their results provide the first solid evidence that some personality disorders, rather than illnesses, could be sexually selected evolutionary strategies. “These strategies are supposed to be ancestral,” he says. “Some of them, such as impulsivity-boldness, probably predate humanity itself.”