"This was not, we think, a psychiatric problem or a characterological defect because there is substantial evidence that during this same time, there was a tumor growing in her brain, in the centers of the brain that affect and control, logic, reasoning and, most importantly, judgment," attorney Eugene Iredale said at a news conference Thursday.
O'Connor sat next to him with her head lowered.
O'Connor didn't plead guilty this week and the charge is played in abeyance for two years, Iredale said.
"It is fair to say in the last eight to 10 years a multiple amount of tragedies have befallen a person who was a great civic leader -- one of the sweetest, funniest people who ever existed in our city's history," the attorney said. "She suffered from terrible loneliness. She began around 2001 to gamble heavily."
"Although it's not fair of us to say there is no moral culpability, Maureen acknowledges doing something she ought not to have done," he added.
Photographs of her head after surgery show a fluid-filled cavity without brain matter at all, he said.
From 2000 to 2008, O'Connor gambled in Las Vegas, Atlantic City and San Diego casinos, court papers said. In 2008, when she became nearly broke, she began to siphon off funds from the R.P. Foundation and continued the activity into 2009, court documents said.
To fund her high-stakes gambling, she had liquidated her savings, sold several real estate holdings, auctioned valuables, and obtained a third mortgage on her home in La Jolla, California, the documents say.
O'Connor allegedly bankrupted the foundation and tried to avoid paying federal income taxes on the charity's money by characterizing what she took as "loans," court papers say.
"Despite having limited, if any, assets other than the funds misappropriated from the foundation, defendant continued high-stakes gambling," the documents say.
By March 2009, O'Connor allegedly had paid off casinos' gambling markers, or lines of credit, but hadn't repaid the foundation, prosecutors said.
She then enjoyed a streak of "several large gambling winnings after March 2009 that were used to continue gambling, not bring the foundation out of bankruptcy," court papers say.
Prior to 2008, the foundation funded such philanthropies as City of Hope, the Alzheimer's Association, Sharp Healthcare, Little Wishes Foundation, San Diego Hospice and the John Burton Foundation, authorities said.