Christopher Pittman is charged with the November 2001 shooting of his grandparents and burning down their home in Chester, South Carolina. His attorneys blame the antidepressant Zoloft, reports CBS' Erin Moriarty.
"He was a 96-pound, 12-year-old boy acting under the influence of a powerful mind-altering drug," said defense attorney Andy Vickery. "That drug was Zoloft."
Vickery told the jury that the medication made the teenager psychotic and unable to tell the difference between right and wrong.
This kind of defense has been used before without much success, but sometimes timing is everything. Last September, an FDA advisory panel determined that some anti-depressants, including Zoloft, can alter the behavior of some patients under the age of 18 - even causing mania and increased suicide attempts.
Former FDA scientist Dr. Richard Kapit, who once approved Zoloft for human clinical trials, is now expected to testify for Chris Pittman's defense.
"Here was a 12-year-old boy who, through no fault of his own, may have committed a crime under the influence of that drug, and that if in fact, he was put on trial as an adult and found guilty, there's a possibility for a miscarriage of justice," Kapit said.
In a statement, Pfizer, the maker of Zoloft, says there is "no scientific evidence to establish that the drug contributes to violent behavior in either adults or children."
Prosecutors agree. They say that Chris Pittman is a cold blooded killer who took his grandparents' lives after they disciplined him.
"What could be more evil and devoid of social duty than taking a shotgun to 60-year-olds who are laying in bed asleep?" asked prosecutor Barney Giese.
If convicted, Pittman -- only 12-years-old at the time of the killings -- could go to prison for life. But the defense is hoping that putting the drug on trial, too, will raise enough reasonable doubt in the minds of jurors.