Democracy, the separation of judicial powers and the free press all evolved for essentially one purpose – to reduce the chance of leaders becoming power addicts. Power changes the brain triggering increased testosterone in both men and women. Testosterone and one of its by-products called 3-androstanediol, are addictive, largely because they increase dopamine in a part of the brain’s reward system called the nucleus accumbens. Cocaine has its effects through this system also, and by hijacking our brain’s reward system, it can give short-term extreme pleasure but leads to long-term addiction, with all that that entails.