WHEN we think of the qualities we seek in visionary leaders, we think of intelligence, creativity, wisdom and charisma, but also the drive to succeed, a hunger for innovation, a willingness to challenge established ideas and practices.

But in fact, the psychological profile of a compelling leader — think of tech pioneers like Jeff Bezos, Larry Ellison and Steven P. Jobs — is also that of the compulsive risk-taker, someone with a high degree of novelty-seeking behavior. In short, what we seek in leaders is often the same kind of personality type that is found in addicts, whether they are dependent on gambling, alcohol, sex or drugs.

How can this be? We typically see addicts as weak-willed losers, and chief executives and entrepreneurs are people with discipline and fortitude. To understand this apparent contradiction we need to look under the hood of the brain, and in particular at the functions that relate to pleasure and reward.

As a key motivator, pleasure is central to learning; if we did not find food, water and sex rewarding we would not survive and have children. Pleasure evokes neural signals that converge on a small group of interconnected brain areas called the medial forebrain pleasure circuit — tiny clumps of neurons in which the neurotransmitter dopamine plays a crucial role.

This dopamine-using pleasure circuitry, refined over millenniums of evolution, can also be artificially activated by some, but not all, psychoactive substances that carry a risk for addiction, like cocaine, heroin, nicotine or alcohol. Our brain’s pleasure circuits are also hard-wired to be activated by unpredictable rewards: While a roulette wheel is spinning or horses are on the track, we get a pleasure buzz even if we don’t get a payout in the end. Uncertainty itself can be rewarding — clearly a useful...