Las Vegas killer Stephen Paddock took Valium for anxiety, tried to sue casino after fall

Las Vegas gunman Stephen Paddock took Valium for anxiety and once described himself as the "biggest video poker player in the world" - betting as much as $US1 million a night, according to a report.

Paddock took Valium at times for anxiousness and had a doctor who prescribed it to him on retainer, CNN reported.

Paddock was deposed on October 29, 2013, as part of a civil lawsuit against the Cosmopolitan hotel in Las Vegas, where he slipped and fell on a walkway two years prior.

CNN obtained a copy of the 97-page document, which the deposition now turned over to the FBI.

"Nobody played as much and as long as I did," Paddock said, adding that in 2006 he gambled on average "14 hours a day, 365 days a year."

"I'll gamble all night," he said, in what CNN called the first account of his life in his own words. "I sleep during the day."

Paddock at times seemed to come off as arrogant and sarcastic during the deposition, according to CNN.

When he gambled he rarely drank alcohol, his testimony said, because "at the stakes I play, you want to have all your wits about you, or as much wit as I have".

"Each time I push the button, it will range from $100 to $1,350," which he described was "not a lot of money."

Paddock wagered up to a million dollars a night while walking around in sweatpants and flip-flops.

This is the picture Paddock painted of himself four years before her opened fire on a crowd of concertgoers, killing 58 people in the world mass shooting in modern American history.

A 2013 court document provides new details on the life of the Las Vegas shooter. Photo / AP

Kept doctor 'on retainer'

While his testimony offers little insight into what could have prompted his killing spree, he said he had no mental health issues, criminal records or addiction habits.

However, he revealed he was prescribed Valium "for anxiousness" and kept his doctor "on retainer".

Paddock was asked whether he had a good relationship with the doctor who prescribed him the pills.

"He's like on retainer, I call it, I guess," Paddock said of Winkler. "It means I pay a fee yearly ... I have good access to him."

Paddock worked for a time as an Internal Revenue Service agent, then began to invest in real estate, CNN reported.

There was no discussion of guns in the court deposition, except for Paddock's confirmation that he had a concealed weapons license in Texas.

Paddock, who described himself as "happy-go-lucky," lost his lawsuit against the Cosmopolitan Hotel, CNN said.