A federal appeals court considered Wednesday whether a paranoid schizophrenic should be forcibly medicated so that he can stand trial on bank robbery charges in a case that could help shape just how far the government can go to make sure the mentally ill are competent to stand trial.

Michael Diaz was charged in April 2004 with two armed bank robberies in Atlanta and represented himself at his first trial, despite concerns he was delusional. He was convicted and sentenced to more than 48 years in prison, but the 11th Circuit Court of Appeals reversed the conviction.

Prosecutors told federal judges Wednesday that Diaz would only be competent to stand trial again if he was forcibly medicated. Diaz's attorney said the drug injections could have life-threatening consequences and violate his constitutional rights.

The judges peppered Diaz's attorney with questions that suggested they sided with prosecutors, even though the Supreme Court ruled in 2003 that forcible medication should be used rarely. The nation's top court said then that forcible medication should only be used if less intrusive alternatives cannot achieve the same results. Few courts have since tried to interpret exactly what the ruling means.

"Before they tie someone down and inject them with mind-altering substances, they should do everything possible to establish that they have no alternative," said Diaz's attorney, Tim Saviello. "And I don't think they did that."

A federal judge found Diaz incompetent to stand trial in May 2009, and sent him to a rehabilitation center for four months of treatment. Six days later, doctors recommended that forcing him to take the medications was the best option, and a judge agreed. Diaz appealed the decision, and the case is now again before the 11th Circuit.

Assistant U.S. Attorney Zahra Karinshak said Diaz had been dismissive of medical workers and spent most of his time working on legal papers when he was asked to submit to treatment.

"There has been an attempt to offer him treatment and he has consistently denied it," she said. "He doesn't believe he is mentally ill and he doesn't think it will help him."

During his first trial, Diaz said his name was "D'Ineiehaimaye" and refused to acknowledge he was Michael Diaz. He rambled incoherently at times, called himself "sacred" and said "I am an autonomous religious faith, living in a liberty establishment," according to court records.

The three-judge panel did not immediately issue a ruling. But U.S. Circuit Judge Stanley Marcus repeatedly questioned what alternatives doctors should have pursued since Diaz repeatedly refused treatment.

Saviello countered that doctors should have worked harder to persuade Diaz to voluntarily take the medications, which he said can be frightening and painful and, in rare cases, have life-threatening consequences.

"When treating schizophrenia you have to establish a solid trust base with the patient," he said. "And how can you do that in six days?"

George Annas, a bioethics expert at Boston University who has written about the issue, predicted Diaz's case could go to the Supreme Court if the panel rules against him. Legal experts were watching to see if the court offers new guidance on the contentious issue, he said.

"Any ruling can help flesh it out," said Jim Cohen, a criminal law professor at Fordham Law School who specializes in mental health issues. "They can conceivably craft a specific ruling that doesn't provide much guidance to other courts, but it's likely that a ruling in this case will guide others."

The federal government did not immediately release details about how many suspects have been forcibly medicated, but experts say that it very rarely happens. There are, however, judges in several high-profile cases who have recently issued similar orders.

An Arkansas judge in May ordered a Little Rock man charged with killing his mother to be forcibly medicated at the urging of his defense attorney. And a Utah judge in 2008 ordered a woman charged in the kidnapping of teenager Elizabeth Smart to be forced to take medications.