ALBANY — Gov. David Paterson’s embattled chief of staff Charles O’Byrne had to pay nearly $300,000 in overdue state and federal taxes, penalties and interest — almost $100,000 more than previously reported, O’Byrne’s tax attorneys said Wednesday.

The lawyers also said O’Byrne sent a last check for $3,600 to tax officials on Tuesday, days after Paterson’s office said all the debts were fully paid. They said the check cut Tuesday was an intentional overpayment mailed as a precaution to duplicate a September payment that hadn’t yet been posted to O’Byrne’s account.

The lawyers, Henry Berger and Richard Kestenbaum of Manhattan, released no checks or other records that proved a payment was made in September.

The lawyers also detailed the mental illness O’Byrne has blamed for his failure to file tax returns from 2001 through 2005. O’Byrne suffered three bouts of clinical depression and received therapy and medication, but is no longer on medication, they said. The last occurrence was in late 2006, when Paterson was elected lieutenant governor, and weeks into 2007, when O’Byrne was the lieutenant governor’s chief of staff making $178,500 a year.

O’Byrne said he informed Paterson of the debt and illness in 2004 and again in 2007. Paterson has confirmed that account.

His attorney said O’Byrne suffered an established syndrome that affects high-functioning professionals and leads to failure to meet financial obligations when suffering clinical depression.

Mental health references and the group Mental Health America, a nonprofit support group, couldn’t immediately identify a syndrome associated with nonpayment of taxes, although there is widespread procrastination when it comes to filing tax returns and it could be a sign of depression, the references stated.

The tax attorneys said O’Byrne never sought to use his illness to delay paying the back taxes, but that a tax attorney probably would have helped do that if he had consulted a lawyer.

O’Byrne’s attorneys said he paid $51,303 in back state taxes, $16,711 in penalties and $12,905 in interest.

He also paid $127,018 in federal taxes, $50,836 in penalties and $34,005 in interest on the federal debt.

A tally provided Wednesday said O’Byrne was credited by tax agencies with paying about $30,000 of the total debt this year, though the lawyers said some payments were credited months after they were submitted.

O’Byrne, a former Catholic priest who is also a lawyer, said he made the tax payments with loans of $5,000 to $20,000 from his sisters. He also got loans of $60,000 to $100,000 from friends Jean Kennedy Smith, the sister of Sen. Edward M. Kennedy, and real estate lawyer Brian Krisberg. The lawyers wouldn’t break out the details, but said O’Byrne will pay interest.

O’Byrne’s lawyers said no money was accepted from anyone doing business with the state.

The records were shown Wednesday afternoon in Manhattan and Albany, but didn’t include O’Byrne’s personal tax returns. Some records were available for reporters to reviewed, but not copy.

The state Senate Investigations Committee is looking into the O’Byrne case and whether there should be greater scrutiny of powerful figures in state government.