If we are to prevent disasters such as a re-run of the global financial crisis or an escalation of conflict in the Middle East , the warnings inherent in the tales of Ancient Greece could demonstrate important lessons.

The phenomenon of exuberant overconfidence (hubris) and subsequent humiliation or destruction (nemesis) of powerful leaders has played out throughout history.

Senior figures in politics, finance, business and academia told a conference at the Judge Institute in Cambridge this week that current leaders must become self- aware of hubristic tendencies in themselves, and take active steps to avoid the development of Hubris Syndrome (HS), an acquired personality disorder which unchecked, can result in disastrous decision-making. It tends to remit on leaving office.

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HS was first described in 2009 by Lord David Owen, a neurologist and former Foreign Secretary. With US colleague Jonathan Davidson, he described its characteristic pattern of exuberant overconfidence, recklessness and contempt for others, displaying Bertrand Russell’s ‘intoxication of power’.

Four British Prime Ministers (Lloyd-George, Chamberlain, Thatcher and Blair) and one US President (George W Bush) met the clinical diagnosis of HS. Owen defined HS as a ‘disorder of the possession of power, particularly power associated with overwhelming success, held for a period of years and with minimal constraints on the leader.’

It is not just political leaders who are vulnerable to HS but those in positions of power in any area of society: business, education, health and many others.

‘Hubris is present in all of us. It’s not inevitable, but the pressures are there. The worry is when people give way to it,’ said Manfred Kets de Vries, psychoanalyst and Distinguished Professor of Leadership Development at INSEAD.

Many people who reach senior positions have done so through well ordered selection procedures. They appear normal and well balanced. HS is a personality change. The longer the position is held, the more likely HS is to develop.

‘Think normal, but then think: they may change’, Owen said.

Like Post Traumatic Stress Syndrome, HS has met some resistance from the medical establishment.

According to Dr Gareth Owen, Clinical Senior Lecturer at the Institute of Psychiatry: ‘The idea of power having a relationship to psychopathology is new to medicine. The question of whether it can be prevented, screened or treated is not yet clear. More research is needed in recognising its signs and symptoms if we are to find more effective interventions.’

Professor Nick Bouras of The Daedalus Trust, a charity which seeks to promote the understanding of, and research into, personality changes associated with the exercise of power by leaders in all walks of life believes that ‘leadership gets harder, yet the need for good leaders is greater than ever. More needs to be done across a much wider cross-section of society and disciplines.’

Striving for the top job in a time of recession and uncertainty requires stamina and determination, as well as ability. The qualities which a Board may look for in a Chief Executive Officer may be the ones which make them more susceptible to HS.

‘There are jobs which need an heroic figure, larger than life, who can propel something from space A to space B’, said Kets de Vries. ‘Once there, you are surrounded by walls, mirrors and liars. Whoever learnt anything from someone who agreed with them?’

Adlai Stevenson said that ‘flattery is alright if you don’t inhale’, but the problem is – who will tell a CEO the truth, when their ego is very actively engaged? Politicians have the beauty pageant of polls, and constant Press scrutiny. The CEO frequently lacks reality testing.

Martin Taylor, ex-CEO of Barclays believes that in susceptible individuals, excessive remuneration can quickly be seen as deserved, and unfavourable comparisons with others ‘adds layers of resentment to the millefeuille of vanity. It’s all too easy, infected by a trading mentality, to develop a gambling streak.’

Splitting the role of CEO and Chairman is crucial to maintaining perspective.

‘There are many handbooks on how to be a good CEO, but hardly anything on the role of Chairman. Boards are often reluctant to act until faced with catastrophe. It’s vital that the Chairman can speak candidly to the CEO. The difficulty comes when their personal and professional relationships are in conflict.’

Professor Dame Sandra Dawson, KPMG Professor of Management and Fellow of Sidney Sussex College, Cambridge emphasised the need for periods of reflection, which are increasingly difficult to secure when constant CEO access is both possible and expected. Even more important is knowing when to leave:

‘Most CEOs see the same issues recur two or three times during their tenure. Each time, they may believe they find the right solution, but its important to come to these problems with fresh eyes. You are not always as good as you think you are. I hope that the person who succeeds me will do an even better job. That way the enterprise will continue to thrive.’

Martin Taylor agrees: ‘When a job is exceptionally demanding and interesting, and you are engaged both intellectually and emotionally, it is hard to give up. In my view, it’s better to leave when people are still sorry to see you go – or at least say they are.’

Fixed terms in Parliament, similar to the US system are seen by Lord Owen as an effective check on political power, and the risk of political leaders developing HS. The democratic system is also important. Owen believes that Cameron’s recent decision to take ‘limited action’ against Syria was ‘hubristic.’ While Cameron’s prompt capitulation to Parliament’s will suggested he was not yet at risk of HS, Owen views Parliament’s vote against military action as ‘the most important during my political career. It was literally world-changing, gaining Obama time and the opportunity to consult Congress.’

Effective checks against leaders developing HS need to be strengthened. Yet democracy and boards can only do so much.

Hubris is one of the world’s most renewable resources. The Temple at Delphi bore the inscription: Know Thyself. Ancient Greece recognised both the problem and the solution.

‘Hope, humanity, humility and humor: it’s is our best protection against developing HS,’ Kets de Vries said.

Professor Christoph Loch, Director of the Judge Business School’s recommendations to protect yourself against HS: