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 attribute for high-risk, high-reward business ventures.so why do some people become addicted to drugs, alcohol, gambling or sex while others can indulge in a moderate, noncompulsive manner? one hypothesis is that addicts feel those pleasures unusually strongly and are motivated to seek them more intently. it’s reasonable, but wrong. evidence from animal experiments and human brain scans indicates that the opposite is true: addicts want their pleasures more but like them less. we’re now starting to understand the biology behind the blunted pleasure of addicts. from studies comparing identical and fraternal twins, it is estimated that genetic factors account for 40 to 60 percent of the variation in the risk for addiction. but we are only in the early stages of understanding the role of genes in addiction; there is no one “addiction gene,” but it is likely that a large number of genes are involved in this complex trait.crucially, genetic variants that suppress dopamine signaling in the pleasure circuit substantially increase pleasure- and novelty-seeking behaviors — their bearers must seek high levels of stimulation to reach the same level of pleasure that others can achieve with more moderate indulgence. those blunted dopamine receptor variants are associated with substantially increased risk of addiction to a range of substances and behaviors.is there a silver lining to the addictive personality? some of our most revered historical figures were addicts — not only the obvious creative types like charles baudelaire (hashish and opium) and aldous huxley (alcohol and the nonaddictive hallucinogens mescaline and lsd), but also scientists like sigmund freud (cocaine) and warriors and statesmen from alexander the great and winston churchill (both known to be heavy drinkers) to otto von bismarck, the unifier of germany, who typically drank two bottles of wine with lunch and topped them off with a little morphine in the evening.leaders in america rarely admit to addictions in public, but one recent example is henry t. nicholas iii, a founder of broadcom, a multibillion-dollar company that makes microchips for cellphones, game consoles, wireless headsets and other electronic devices. starting with a $10,000 investment, mr. nicholas and his partners created a company that now has 9,000 employees and 5,100 patents. along the way, he struggled with alcohol, cocaine and ecstasy; he entered a rehab program in 2008. (he also successfully fought off criminal charges related to backdating stock options and drug distribution.)the risk-taking, novelty-seeking and obsessive personality traits often found in addicts can be harnessed to make them very effective in the workplace. for many leaders, it’s not the case that they succeed in spite of their addiction; rather, the same brain wiring and chemistry that make them addicts also confer on them behavioral traits that serve them well.so, when searching for your organization’s next leader, look for someone with an attenuated dopamine function: someone who is never satisfied with the status quo, someone who wants the feeling of success more than others — but likes it less.