(NEW YORK) -- U.S. Army Staff Sgt. Robert Bales, who is facing sentencing by a military court for killing 16 civilians on a rampage in Afghanistan last year, might have faced a perfect storm of stress, which included the use of mefloquine hydrochloride, an antimalarial drug given routinely to soldiers in that part of the world.
Mefloquine was developed by the U.S. military and has been used for more than three decades by the government to prevent and to treat malaria among soldiers and Peace Corps workers.
But the drug can cause varying neurological side effects five to ten percent of the time, according to Dr. David Sullivan, an infectious disease specialist at Johns Hopkins Malaria Research Institute in Baltimore.
A study of Food and Drug Administration adverse-event reports from 2004 to 2009 published in the journal PLOS One lists mefloquine as a drug that has been associated with violence toward others.
Sullivan said the military widely uses antimalarial drugs in Afghanistan, but mefloquine is not the first choice.
"Tens of millions of people take it," Sullivan said. "Honestly, you cannot implicate any one thing. To put it all on mefloquine is not fair. [Bales] already has a predisposition because of a traumatic brain injury and he has taken this drug in a stressful situation. You have to put it in context here. … But you can't exclude it."
Bales, 39, a father of two from Washington state, has admitted to the killings after he left his remote outpost in the southern Afghan province of Kandahar to go on a shooting spree in two nearby villages. The pre-dawn attack left 16 villagers dead and six injured. Nine of those killed were children.
Bales suffered from head and foot injuries while deployed in Iraq and might have been traumatized by seeing one of his fellow soldiers lose a leg in an explosion hours before the killings, according to testimony.
By pleading guilty, he avoided the death penalty, but Bales still faces life imprisonment, with or without parole, at a sentencing trial set for next month.
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