Greater Good Magazine ran an article called "The Power Paradox."
Here's a snippet.
Perhaps more unsettling is the wealth of evidence that having power makes people more likely to act like sociopaths. High-power individuals are more likely to interrupt others, to speak out of turn, and to fail to look at others who are speaking. They are also more likely to tease friends and colleagues in hostile, humiliating fashion. Surveys of organizations find that most rude behaviors—shouting, profanities, bald critiques—emanate from the offices and cubicles of individuals in positions of power. My own research has found that people with power tend to behave like patients who have damaged their brain's orbitofrontal lobes (the region of the frontal lobes right behind the eye sockets), a condition that seems to cause overly impulsive and insensitive behavior. Thus the experience of power might be thought of as having someone open up your skull and take out that part of your brain so critical to empathy and socially-appropriate behavior.
Power may induce more harmful forms of aggression as well. In the famed Stanford Prison Experiment, psychologist Philip Zimbardo randomly assigned Stanford undergraduates to act as prison guards or prisoners—an extreme kind of power relation. The prison guards quickly descended into the purest forms of power abuse, psychologically torturing their peers, the prisoners. Similarly, anthropologists have found that cultures where rape is prevalent and accepted tend to be cultures with deeply entrenched beliefs in the supremacy of men over women.
This leaves us with a power paradox. Power is given to those individuals, groups, or nations who advance the interests of the greater good in socially-intelligent fashion. Yet unfortunately, having power renders many individuals as impulsive and poorly attuned to others as your garden variety frontal lobe patient, making them prone to act abusively and lose the esteem of their peers. What people want from leaders—social intelligence—is what is damaged by the experience of power.