Pat Sullivan, File, Associated Press
FILE - In this June 29, 2009 file photo, billionaire R. Allen Stanford smiles as he is escorted out of the federal courthouse in Houston. Federal prosecutors say Thursday, Dec. 15, 2011 that jailed Texas financier Stanford, who was declared incompetent to stand trial earlier this year, is now competent to be tried next month. Stanford is accused of bilking investors out of $7 billion in a massive Ponzi scheme.

HOUSTON — Jailed Texas financier R. Allen Stanford is now competent to be tried next month on charges he bilked investors out of $7 billion in a massive Ponzi scheme, federal prosecutors said Thursday.

The prosecutors' assertion comes ahead of a mental competency hearing on Tuesday, which will be used by a federal judge to determine if Stanford's Jan. 23 trial will go forward.

Stanford's attorneys say his addiction to an anti-anxiety drug, as well as a brain injury he suffered in a jail fight, left him unable to think clearly or help in his own defense. He was declared incompetent to stand trial earlier this year.

The financier spent about eight months this year being treated in a North Carolina federal prison hospital for the drug addiction he developed while jailed in Houston.

"Based on its extensive analysis, (the prison hospital) concluded that Stanford 'does not suffer from a mental illness which would interfere with his ability to understand the nature and consequences of the proceedings against him or to assist properly in his defense,'" prosecutors wrote in court documents filed Thursday.

In his own court filing, Ali Fazel, one of Stanford's attorneys, said the brain injury the financier suffered in a September 2009 jail fight as well as the various medications he was given while jailed in Houston "exacerbated the accused's medical condition."

Stanford "does not have the present mental capacity to effectively assist his attorneys in preparing his defense," Fazel wrote.

A gag order is preventing attorneys from discussing the case outside of court filings.

Stanford is also apparently claiming a new illness: retrograde amnesia. The financier says the injuries he suffered in the jail fight have left him with complete memory loss of all events in his life prior to that assault.

Prosecutors said that Stanford claims he can't remember past events in his life, including "details of his business and banking operations." Stanford also claims that family members have had to educate him on his personal history and that he "indicated feeling bad after being informed by his family that he was known as a 'womanizer.'"

But doctors at the prison hospital say Stanford's memory loss claims are "not credible" and that neurological testing of the financier showed strong evidence or "malingering" or faking symptoms, prosecutors said. A neurologist also found no evidence of damage to any part of Stanford's brain that processes memory, they said.

Stanford and three former executives of his now-defunct Stanford Financial Group are accused of orchestrating a colossal pyramid scheme by advising clients from 113 countries to invest more than $7 billion in certificates of deposit, or CDs, at the Stanford International Bank on the Caribbean island of Antigua, promising huge returns.

Authorities say Stanford and the executives fabricated the bank's records, bribed Antiguan regulators with investors' money from a secret Swiss bank account and misused funds to pay for Stanford's lavish lifestyle.

Stanford became a billionaire whose financial empire stretched across the U.S., the Caribbean and Latin America. His attorneys say he ran a legitimate business.

Stanford has been jailed since he was indicted in June 2009 by a federal grand jury in Houston, where his companies were headquartered.

After a superseding indictment in May, Stanford is facing 14 counts, including wire and mail fraud. He originally faced 21 counts.