Zimmerman's attorney: Low dose of marijuana can lead to aggression

The attorney for Florida murder suspect George Zimmerman says that even a small level of marijuana in the bloodstream could increase violent behavior.

CNN host Piers Morgan on Monday night asked Zimmerman attorney Mark O'Mara why it was important that Trayvon Martin had a small amount of marijuana in his system during the fatal confrontation last year. Judge Debra Nelson has ruled that the jury can see toxicology results showing THC in Martin's system.

"Any level of pot in his system could have some effect," O'Mara said. "And of course that falls in line with what Zimmerman stated in his first couple of moments with the non-emergency operator when he said that it looks like he's on drugs or something."

Morgan, however, was skeptical that a small amount of marijuana had any importance.

"Well, actually, there are some studies out there -- particularly with young males -- that suggest that even low levels of cannabis use can lead to aggression," O'Mara responded. "So, the question is not how much, but if in fact there has been some effect and if that effect was noticed by George Zimmerman then I think it is relevant. After all, if we're going to talk about what George Zimmerman may have read in coursework two, three, four years ago then I think what Trayvon Martin had smoked or had in his system somewhere between two and four hours before the event is certainly something the jury should consider."

Watch video, uploaded to YouTube, below: