World leaders who make war tend to have a particular profile called “high need for power”. American presidents who show this are, throughout history, more likely to take their countries into war than those who don’t. Dwight Eisenhower didn’t show it for instance, while George W Bush did.

“Need for power” was identified by the great psychologist David McLelland as one of three basic, largely drives, which motivate people to different degrees. The need for power—the others are the needs for affiliation and achievement—is where you are motivated to dominate and control what other people want, need or .

In simulations of the Cuban missile crisis where nuclear holocaust between Russia and USA was narrowly averted, people who are high in the need for power acting the role of war room decision makers tend to take actions which would, in 1962, have resulted in nuclear war.

All leaders need to have a certain for power— is too otherwise, and power’s effects on the brain’s act as a sort of anti-depressant. But like all addictive drugs, too much for too long causes dangerous changes in the brain, which include reckless disinhibition, risk-blindness and difficulty in seeing things from other’s perspective: ex UK Foreign Secretary Lord David Owen has described this as the “Hubris Syndrome” which he diagnosed leaders Margaret Thatcher, Tony Blair and George W Bush, among others, as showing.

Few if any leaders can survive more than ten years of power without being tipped into this dangerous state of altered personality and increased desire for even more power. Most democracies have devised constraints—limited terms of office for instance—to counteract such dangerous changes to the brain. Even the Republic of China changes its leadership every ten years.

It is the neurologically-created conceit of many powerful leaders that—in the words of Louis XV of France—“après moi le déluge” (after me, the flood). Power fosters the delusion of indispensability and many political leaders have created havoc in fighting to stay in post because they genuinely believe their abilities are crucial for the survival of their country and that no-one else can do it.

President Vladimir Putin has held power in Russia as President or Prime Minister for approaching 15 years—too long for any man or woman’s brain to endure without dangerous changes which foster recklessness and a blindness to other perspectives. Saturday’s military incursion into Ukraine may be a particularly worrying symptom of this leader’s affliction.

@ihrobertson