Gabriel Magee, 39, a vice president with JP Morgan's corporate and investment bank technology arm, plunged from the building in January, hitting a lower, 9th-floor roof where he was pronounced dead at the scene.

The inquest heard written evidence from a senior toxicologist that Magee, from the United States, was found to have had an alcohol level nearly three times the legal driving limit.

Mark Gibbons, a friend and colleague, said that although he had seemed happy at the time of his death, there had been a previous incident in New York where Magee had sent an email along the lines that he "couldn't handle this" before disappearing for a short while.

However, when he re-appeared he seemed fine, the inquest heard, although he had had a difficult time last August when a project he had been working on was not going well.

The inquest also heard from several witnesses that Magee had been upset in early 2013, a year before his death, when he split up with his girlfriend.

"He was very depressed ... he would be sobbing uncontrollably, and then laughing hysterically - he had paranoias about all sort of things, a lot of them directed at me or things around me," the ex-girlfriend Lucy Pinches told the court.

She added that Magee had thoughts about life in another universe that she did not understand and that he had continually refused help from those close to him.

(Reporting By Costas Pitas; editing by Stephen Addison)

Stocks treated in this article : JPMorgan Chase & Co., Deutsche Bank AG