For years, Dave felt a compulsion to argue "with anyone about anything" online, he says, whether the topic was gun control or the accuracy of a quote from the movie Top Gun. He trolled under his real name as well as behind more anonymous handles on various message boards and comment sections. He would obsessively check on flame wars he had going when he was supposed to be working, was warned by a boss about his unruly behavior online, and got into such a nasty and lengthy exchange on a local newspaper's message board that the paper shuttered the board for good.

It was only after several friends cut him out of their lives that Dave* realized he had a trolling problem.

"There's a high in getting to be right, and trolls chase that rush," says Dave, now 40. "But there was no 'enjoyment' in feeling a responsibility to make sure people were educated and corrected."

His lack of concern about the consequences of his actions (even when morally, he's in the right), is part of what made him an internet troll, Dave, currently a digital content producer in Southern California, tells me. Dave agreed to speak to Motherboard only on condition of pseudonymity because he's worried about the embarrassment he says he'd feel if he were ever outed as a troll.

Dave's friend wrote him soon after, saying, "I've known you since 10th grade and you're one of my favorite people, but I can't have you in my life anymore." The two haven't spoken since. Dave admits he feels bad about it. But, he tells me, "In the moment, I thought, 'This is totally worth it!'"

In one of the incidents he most regrets, Dave went off on an old friend on Facebook for posting a "super Islamophobic" article that Dave found offensive. He says he was upset with the friend for posting the article in the first place, and that he didn't just call her out for it; he angrily argued about it all day, telling her she didn't care about anyone who wasn't white and Christian, and that she was a terrible person. And when Dave's friend's sister joined into the exchange to argue with Dave, he told her, "fuck you, too!"

Like HanAholeSolo, Dave says he sees similarities between his trolling habit and the effects of other addictions , or what the most recent edition of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-5) refers to as " use disorders ." The DSM-5 defines these disorders as recurrent use of a substance, be it alcohol or cocaine, that "causes clinically or functionally significant impairment."

Some trolls claim that lashing out at strangers online like this can become a hard habit to break. "If you have a problem with trolling it is an addiction just like any other addiction someone can have to something," HanAholeSolo, the redditor with a history of racist and anti-semitic posts who claimed credit for the infamous Trump-CNN wrestling GIF, wrote in a now-deleted mea culpa to his comrades on Reddit in July. "Don't be embarrassed to ask for help."

"If people are harmed or angered by it, who gives a shit if you were just playing?"

Trolls are often portrayed in the media as gleefully malicious, cackling over their keyboards as they anonymously hurl insults and threats at total strangers. But it's becoming increasingly evident that, for some people, trolling isn't just playing an asshole on the internet. As well as being harmful to targets and victims, it's behavior that can become unhealthy for those who, like Dave, seemingly can't resist doing it.

"The goal was to just fool people into responding and debating an issue, and say, 'You're crazy,' or that kind of stuff," says Wallace, a former senior director of the Center for Talented Youth at Johns Hopkins University and current adjunct professor at the University of Maryland University College Graduate School. "But over time, trolling became associated with much more negative things— hate speech , harassment , and cyberbullying —so what the media calls 'trolling' now is kind of a mixed bag."

In the late 1980s and early 90s, "trolling" generally referred to a sort of online prank. It's what some people now call "classical trolling," according to Dr. Patricia Wallace , author of The Psychology of the Internet.

An obstacle to 'treating' hardcore trolls is no one can agree on what trolling is

And it's just as unlikely that therapy would help if they did.

Some psychologists and academics who have studied online trolls do note commonalities between excessive trolling habits and use disorders, though only to a point. They say it's a catch-22: Although trolling is a serious problem for which many people should get psychological treatment, some trolls are unlikely to ever seek it.

Regardless, a more accurate term than "use disorder" to describe the compulsion to troll might be an "impulse control disorder"—a group that includes kleptomania, pyromania, and gambling—"where they have an impulse and can't stop themselves, even when it can have harmful consequences," says Dr. Ramani Durvasula, a licensed clinical psychologist, professor at the California State University, Los Angeles, and author of Surviving Narcissists.

At the same time, Dave has never had a substance misuse problem himself. So the comparison between these kinds of physical addictions and excessive trolling isn't grounded in real-life, personal experience.

"But it also has all these politicized problems," she adds. "For example, when 'trolling' is applied to white nationalism , it minimizes or white washes what the bigots are saying. It doesn't refer to behavior in terms of its impact, but under some presumed motive of playfulness. And it doesn't matter. If people are harmed or angered by it, who gives a shit if you were just playing?"

The very term "troll," in fact, has been rendered meaningless due to overuse, Whitney Phillips , a troll researcher and author of This Is Why We Can't Have Nice Things: Mapping the Relationship Between Online Trolling and Mainstream Culture, tells me. Despite having written books about trolls Phillips herself loathes the term, which she says is now, at best, an imprecise one. (Disclosure: Phillips has written for this website .)

Meanwhile, there is growing interest in the study of trolling, specifically, as digital addictions become more visible and acknowledged as a serious issue, according to Brenda K. Wiederhold, president of the Virtual Reality Media Center and editor of the journal CyberPsychology, Behavior & Social Networking. Yet trolling research is essentially in its infancy; so far, what little exists is based largely on anecdotal and self-reported data.

"Different people describe the same behavior in different ways," Buckels says. "Although some have proposed different 'types' of trolls , there is currently no scientific evidence for these distinctions. There is, however, much psychological research on the personality dimensions that underlie trolling behavior and the distinctions among these traits."

Erin Buckels, a doctoral candidate in psychology at the University of British Columbia and lead author of a 2014 study titled " Trolls Just Want to Have Fun ," agrees that trolling definitions are hard to pin down.

"Some people can get into an argument and be offensive and walk away, just like some can try coke and walk away," Dave says. "But others do it once and are like, 'oh my God, that was great,' then they want to do it all the time."

Whatever the definition, at best, trolls are an internet nuisance, and at worst, a threatening, ugly presence that causes damage to their victims. The question is, are trolls more likely to be people with real psychological issues or just jerks?

A broad definition that might be useful for the purpose of this story is the one Vijay Sinh , a clinical psychologist in New York City, gave me. Internet trolling, Sinh says, "includes following people online and communicating and responding to them in a disruptive, hostile, and at times vengeful manner, often intending to upset or cause a negative reaction or response in the other."

But they'll first have to clear up the issue of terminology, because presently, Wallace says, "it's very messy."

According to Wiederhold, researchers interested in studying trolling are beginning to recognize a need to discern between trolling and cyber victimization. "I think in the next year or so we'll see more research splitting it apart," she tells me.

When researchers do engage with trolls, Phillips notes, any demographic information about them is only surmisable based on what the individuals post when they troll. For example, Phillips says someone who posts misogynist comments is likely to be male, just as someone who uses racist slurs is probably white. Then again, she warns, if you're a researcher engaging with trolls it's safe to assume that much of what they tell you isn't true. They are trolls, after all.

"Could a troll troll often enough that those changes would occur in the brain? Maybe. But I can't say that I've seen any patients who claimed trolling was an addiction," Cash says, adding, "I certainly have had clients for whom trolling behavior is part of the bigger picture of their internet addictions."

To be considered an "addiction," the behavior has to be done to an extent that the brain actually goes through the physiological changes we associate with use disorders: because dopamine and other neurochemicals related to pleasure are released, the behavior is rewarding. Then you have to do it more and more in order to get the same effect, says Dr. Hillarie Cash, clinical director of reSTART, a rehab facility in a forest outside Seattle that treats adults and teens for internet gaming and digital addiction .

"Should trolls receive treatment? Absolutely. But is it an addiction? I don't think we're there yet."

Trolling can feel rewarding in its early phases, in the same way alcohol use or gambling can, Durvasula says. Similarly, over time it might also turn into behavior that feels difficult to control. But experts stop far short of lumping trolling in with other use disorders like alcoholism or drug misuse. "Trolls" do what they do for a variety of reasons that don't necessarily indicate a psychiatric disorder, according to Durvasula.

"Trolling gives toxic personality types the perfect reward," Neo says. "They get to witness their effects. … and every time they do that, dopamine floods their brain synapses, firing off their reward neurocircuitry. It's the perfect reinforcement to repeat the behavior over and over again."

It also might feel to some people like an addiction of sorts to power and domination, according to Dr. Perpetua Neo, a clinical psychologist in Brighton and Hove in the UK.

"When we talked about how she spent her time and things she enjoyed doing, it emerged that a lot of time, effort, and energy was being spent fighting battles online, with little awareness about how much this was related to her problems with people 'in the real world,'" Sinh recalls.

In addition to consciously feigning a response to therapy, another obstacle can be a lack of self-awareness often present in these personality types, Sinh says. One of her patients is a high-school teacher who spent a significant amount of time correcting strangers' grammar and writing errors in internet forums and on blogs. But the reasons behind the teacher seeking therapy, Sinh says, were a troubled marriage, faltering relationship with her children, and a history of insubordination and interpersonal conflicts at work.

"Dark" personality types tend not to have any inclination to develop the empathy they're lacking, according to Neo, who was not involved with Buckels's 2014 study. "So if they ever want to 'treat' the problem, it's because they're getting into trouble or someone's issued an ultimatum to them," she tells me. "Even then, any form of treatment is often done at face value. They're good at pretending to show remorse and appear to be progressing, even if there's no real motivation to change."

They're dishonest when it suits their purposes and lack humility and emotional empathy for others, she continues. People with "dark" personality traits are unlikely to seek psychological treatment for anything unless forced to do so, Buckels says, noting, "They are exactly the way they want to be. Other people are the problem."

People who score high on "dark" personality trait measures enjoy making an impact on the world and are highly competitive, according to Buckels. "They aim to 'win,'" she says, "whatever that means to them."

It would be an overstatement to say all trolls have psychological problems. In their 2014 study, Buckels and her co-authors did note a strong association between people who engaged in trolling and malevolent personality traits, particularly Machiavellianism, narcissism, psychopathy, and sadism, in particular, she says. These comprise what's referred to as the " Dark Tetrad " of personality traits.

"Should trolls receive treatment?" asks Wiederhold. "Absolutely. But is it an addiction? I don't think we're there yet. I'd like to see more studies done on it."

Although trolling doesn't currently fit the clinical definition of a use disorder, many experts say the behavior is nonetheless unhealthy and warrants therapy.

Bishop, whose work is not carried out on behalf of any institution or anyone other than himself, publishes his own journal dedicated to trolling, says he has a "trolling museum" in his house, proudly notes that he keeps a running list of people who have blocked him on social media, and says he maintains several websites that troll visitors to varying degrees. One of those sites details his own trolling, and another mocks a man with the same name as Bishop but whom Bishop feels is intellectually inferior to him. Bishop claims there are three sites dedicated, in turn, to trolling him, and also says he thinks public figures "deserve" to be trolled: He's harassed local Welsh politicians, author Richard Dawkins, and comedians Russell Brand and Ricky Gervais, the latter of whom, Bishop brags, blocked him on Twitter.

So-called RIP trolls, for example, might find it hypocritical and disingenuous when strangers post condolences online about people they didn't know who have died, says Jonathan Bishop, a troll "researcher" in Wales who admits to trolling frequently himself. In one of his blogs, Bishop describes how he argued on Facebook that text in certain speeches made by Barack Obama and former British Prime Minister Tony Blair are "nearly identical" to speeches made by Adolf Hitler.

Aside from trolls' typical lack of remorse, the high levels of callousness and impulsivity typically seen in these personality types mean they're unlikely to see trolling as their problem. In Sinh's words, "It's their target's problem for saying, being, or doing XYZ in the first place."

"As she saw it, these were things that others in her line of work had to frequently endure and grow a thick skin toward," Sinh says. "Writing mean comments on others' blogs or about their work was a way of carrying forward what had been done to her."

Sinh told me about another client, an ambitious but insecure model, who revealed during her sessions that she frequently posted "disparaging and humiliating" comments anonymously on beauty blogs and vlogs.

Bishop says he's able to put others in situations that "help them see the error of their ways" because he says he understands other people's personalities so well. He refers to himself as an "educational troller."

"I'd say I kind of am overeducated with too much time on my hands," Bishop says. "I guess it's kind of like chess, except the players are real people."

According to Wallace, author of The Psychology of the Internet, some people are proud to call themselves trolls because they think of themselves as righteous vigilantes. (Christians and atheists are two of Bishop's favorite targets.) Bishop giggled often when describing his trolling to me during a recent Skype interview, but when pressed, he couldn't articulate why he gets such a charge out of "proving" strangers wrong about various topics, even when there is no factual basis to the point he's trying to make (like trying to argue Obama and Blair lifted speech lines from Hitler). Evidently lacking in introspection, he couldn't tell me how that makes him feel.

This appears to reflect another issue that makes diagnosis difficult: In the DSM-5, disorders are diagnosed on the basis of whether an individual who might have the disorder is experiencing "impairment, distress or both." This presents a problem when attempting to diagnose problematic trolling. But again, just because they don't want help doesn't mean they don't need it.

"We may all occasionally disagree with someone online or post an unfavorable comment based on our political or social view," Sinh says. "But when we start deriving some pleasure or glee by putting someone down or making someone's life miserable online and remaining anonymous and therefore protected from consequences, and do this consistently and vengefully, that's when the behavior is no longer innocuous and warrants attention."

Catching trolls early might help

With trolls, "It's hard to know where the performance ends and where the real personality begins," Phillips says. "It's not that they're sociopaths necessarily, it's that they don't have to look at the emotional impact of their behavior except to the extent that it amuses and entertains them. They're just focusing on the punch line."

Trolls who do have dark personality traits might be treatable, depending. Sadism can't be treated, Buckels says, but adds, "Clinicians could probably treat the compulsive aspects of the behavior, and channel sadistic tendencies in a socially acceptable direction."

In addition, there might be some hope in treating younger trolls for whom the behavior isn't as deeply entrenched, says Durvasula, who adds that some of her psychology students have admitted to trolling during student-teacher conferences. Their trolling seemed to reflect the behavioral disinhibition and poor judgment common in young people who may not think through consequences rather than any psychological disorder.

"They recognize afterwards that it's not a nice thing to do," she says. "But since it's anonymous and everyone is doing it, they are not that contrite."

When they're called out on the potential harmfulness of their behavior, however, Durvasula says her students do seem able to reflect on what they've done and express some remorse.

"There's more of a chance you can train younger people to empathize, help them mature, and learn life skills that will make them less likely to troll," she says. With some intensive therapy that includes socialization and giving them some contingencies, she tells me, a teen patient could be taught about the ramifications of their trolling and to be self-reflective.

Although now well into adulthood, Dave says he was able to overcome his trolling problem slowly, with the help of a therapist, after people he cared about started losing respect for him because of his angry online shenanigans. Yet he recently "relapsed," as he put it, when one of his closest friends from college posted something on Facebook about Trump's alleged Russia ties. Dave couldn't resist arguing with some of his friend's Bible-thumping acquaintances about it.

"This guy is a dear friend of mine, but I was like, 'I cannot let something this stupid go unanswered,'" he says. "Even though I knew exactly what was going to happen."