At Zimmerman trial, marijuana testimony echoes famous Tampa killings

Testimony expected in the George Zimmerman murder trial about whether marijuana can make people violent brings to mind a seminal case that played out decades ago in Tampa and that influenced the way Americans think of the drug.

In October 1933, Victor Licata, a 21-year-old Tampa man, killed his mother, father, two brothers, sister and the family dog with an ax at the home they shared in Ybor City. Police found him crouched in the bathroom, mumbling incoherently. He refused to talk at first but later told police of a dream in which he hit six people with an ax.

A Tampa police detective told reporters that he had investigated Licata earlier and found he was addicted to smoking marijuana cigarettes. The Tampa police chief soon chimed in, saying that even if Licata's marijuana use "only had a small indirect part in the alleged insanity of the youth," he was "declaring now and for all time that the increasing use of this narcotic must stop and will be stopped."

The case became a cause celebre in the press and inspired the anti-marijuana propagandists as American alcohol prohibition came to an end. STOP THIS MURDEROUS SMOKE was the headline on the lead Tampa Times editorial a few days later. Several books, articles and films began to portray normal people driven to insanity by marijuana, including the 1936 film Tell Your Children, also known as Reefer Madness.

The sensational case was used by highly placed antimarijuana officials to steer the debate over whether marijuana was safe, including Federal Bureau of Narcotics Commissioner Harry Anslinger, who cited the Licata case often in pushing for the passage of the Marihuana Tax Act.

He was successful, despite the fact that Licata was later diagnosed with "Dementia Praecox with homicidal tendencies" at the Florida Hospital for the Insane, and doctors did not mention his marijuana usage. It was also learned that his family had a long history of mental illness, and Licata had been identified as mentally ill long before the murder.

The judge in the trial of George Zimmerman has ruled that the defense can introduce a toxicology report that shows Trayvon Martin had the active ingredient of marijuana in his system when Zimmerman shot him dead in February 2012.

The ruling was based in part on the testimony of medical examiner Shiping Bao. He testified last week that the level of tetrahydrocannabinol, or THC, in Martin's blood was so slight it would have had no effect on Martin. But he testified later that further research in preparation for the trial showed the drug might have impacted Martin's behavior in an unknown way.

The defense's question likely to be presented in State of Florida vs. George Zimmerman: Could Martin's drug use have caused the teen to attack George Zimmerman, putting Zimmerman in a position where he feared for his life and fired his gun in self-defense?

What the jury will make of this testimony is unclear. As more states move toward loosening laws to allow legal use of medical marijuana, the stigma associated with America's most-used illicit drug varies wildly.

The federal government's position: Research shows that chronic marijuana use may increase the risk of schizophrenia in vulnerable individuals, and high doses of the drug can produce acute psychotic reactions. But marijuana researchers say the drug works well to relieve certain kinds of pain and helps increase appetite.