But, as famed biographer and history professor Walter Isaacson says in his new biography of the tech giant, released Tuesday by Simon & Schuster, it’s “not in Musk’s nature to leave well enough alone.” 

‘Part of my default settings’

In his latest book, simply titled “Elon Musk,” Isaacson observes that the billionaire businessman takes continual risks. Those closest to Musk say he craves highly intense situations—and Isaacson recalls Musk once saying, “I want to keep taking risks. I don’t want to savor things.” Even after a major business success, Isaacson notes that Musk gears up for the next thing in order to avoid feeling idle.

In one of the conversations Isaacson observed, Shivon Zilis—a venture capitalist and mother to two of Musk’s kids—told the business savant, “You don’t have to be in a state of war at all times. … Or, is it that you find greater comfort when you’re in periods of war?” 

“It’s part of my default settings,” he told her. 

“It was like he was winning the simulation and now felt at a loss for what to do,” Zilis told Isaacson. “Extended periods of calm are unnerving for him.” 

In October, the world’s richest man bought Twitter, despite warnings from his family against the move. “I guess I’ve always wanted to push my chips back on the table or play the next level of the game,” Musk told Isaacson. “I’m not good at sitting back.” 

Is risk-taking addictive? 

In simple terms, risk-taking refers to engaging in a behavior when the outcome is uncertain—and the effects of it can mirror addiction.

The brain’s release of dopamine, a neurotransmitter associated with feeling pleasure, is more intense in response to unexpected rewards, says Gideon Nave, associate professor of marketing at the Wharton School at the University of Pennsylvania. His research focuses on the science of risk-taking. 

“Dopamine has been shown to be released not when we experience a reward per se, but when we are experiencing a reward that is greater than what we expected,” he tells Fortune. 

Take, for example, gambling—it has the potential to become a behavioral addiction because the chance of winning a lot of money feels more pleasurable than the feeling you get from seeing your regular paycheck roll in. Addiction occurs when there is a compulsive urge to engage in a behavior despite harmful consequences. A hope of either feeling good or avoiding discomfort can accompany the compulsive reaction, according to Harvard Health.

“If you get an unexpected reward, your dopamine is going to kick [in], and that’s going to feel very good, and that’s going to also lead you to take more risks,” Nave says. “We know that unexpected rewards are more likely to generate habits and lead to dopamine secretion.” 

Musk’s predilection to continually seek out his next business conquest could be interpreted as an addiction to risk-taking behaviors, according to Nave.

“[If you] invest in some company that only has 10% of succeeding and it ends up succeeding, that’s a massive source of dopamine,” he says, noting that people like Musk are dependent on seeking new sources of thrill—even when they’re already successful at what they do. 

As with any addiction, there are ways to quit, including finding a network of people who can support your behavior change and seeking out professional help. There may also be medications to help ease the process.

Whether due to genetics, the environment, or a combination, people can become addicted to risk-taking—and it’s no surprise they also flock to the uncertain landscape of entrepreneurship.