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Have you ever thought about killing someone? Not plotted it out, necessarily, but fantasized about offing a bully or boss or boyfriend in a desperate search for catharsis?

I wouldn’t encourage you to spend too much time dwelling on all the rejections and confrontations that might have led to such an angry moment, but I do need you to think about those things briefly. I also won’t ask you to name all the definitely valid reasons you might have for wanting to murder—or maybe just punch!—the other person involved, but I suspect that for most people, it has crossed their minds.

What I will say, though, is that you should stop yourself now, and go no further. You wouldn’t want to ruminate.

Colloquially, rumination has a benign meaning: to contemplate deeply. In psychology, rumination isn’t so harmless. It’s marked by intrusive, even obsessive thoughts that return a person to a particular stressor or negative experience, which the American Psychological Association says is strongly linked with the development of major depression. Typically, rumination is spurred by things like past trauma, chronic stress, or neurotic personality traits. Based on new research, there might be another way to spark rumination: to fantasize about killing someone you absolutely hate.

Kai-Tak Poon, an assistant psychology professor at the Education University of Hong Kong, led a team that asked a group of 138 American adults to pick the person they hate the most. Half were asked to fantasize about doing something violent to that person (which could involve murder, but could also just be an angry slap). The other participants were asked to fantasize about taking any neutral action. The results suggested that those who fantasized about aggression were more likely to ruminate, which then lowered their perception of their own well-being. Thinking about hurting a sworn enemy bums people out, even if, on a certain level, the idea is really appealing.

Dennis Reidy, a professor involved with Georgia State University’s Center for Research on Interpersonal Violence, says there’s much scientific evidence for the link. “People who have aggressive fantasies are more likely to be aggressive, whether it’s physically or just a sense of irritability or hostile personality,” he says. “They are more negative people, and are more likely to have negative affect and lower subjective well-being.”

Poon’s study asserts that violent fantasies themselves cause a person to feel worse, but Reidy wouldn’t go that far, because of what he sees as weaknesses in the study’s approach. No measure of the participants’ subjective well-being was taken before they were asked to fantasize, for instance, and more than a dozen participants were excluded from the study’s results because they either couldn’t name a nemesis or couldn’t conjure up a violent fantasy. (Those people sound great.)

Another issue, Reidy says, is that violent fantasy itself is a form of rumination. As Poon’s study notes, rumination can be difficult to stop once it starts. So prompting someone to do it would usually cause the rumination—and its attendant negative effects—to continue. “Anybody who you asked to fantasize [violence] about someone they hate … is going [to] have more negative affect in the moments afterward,” Reidy says. (Poon did not respond to requests for comment.)

Even though a link between graphic fantasies of violence and feeling not so great might sound logical, for much of modern psychology’s history, that link wasn’t assumed. Instead, psychologists preferred catharsis theory, which suggests that venting anger—or pursuing ruminative thought—could help a person let go of negative feelings by working through them. In the past couple decades, though, catharsis theory has been unmoored from the foundation of how psychologists understand aggression. In one discrediting study, participants were provoked with criticism and then asked to hit a punching bag while thinking of the person who criticized them. Relative to a control group who just sat quietly, the punchers felt even more upset after they finished letting it out. If your cup runneth over with anger, you can’t just pour a little off.

Rumination not only appears to fail as a coping strategy for rage and trigger depression, but as Reidy points out, the type of violent rumination considered in Poon’s study is linked to elevated levels of actual violence. Patients receiving mental-health treatment who imagine violence are more likely to behave aggressively, and researchers recommend that treatment to help them focus on dissuading ruminative thinking. And while it’s not easy to divert a person away from intrusive or traumatic thoughts, it can often be achieved through a distracting, peaceful activity or a relaxing technique, like meditation. Going to a kickboxing class might not make you want to punch your sister-in-law any less, but going for a run might.

When testing the parameters of a psychological reaction, one can easily disconnect that thing from the vagaries of human experience and look at it in a vacuum. The participants in Poon’s study were prompted to drum up a murderous rage, but who are the people who have regular violent fantasies in the first place, and why do they have them? Reidy thinks that these fantasies, like rumination and physical aggression, might be more a symptom of a problem than a cause.

“I don’t know that the angry fantasy is what’s driving all the other stuff,” Reidy says. “It’s possible that those are all outcomes of some underlying personality or exposure to violence in youth. I think they’re consequences of something else.”

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