A U.S. Army Staff Sgt. charged with killing 16 Afghanistan civilians may have been on a blind rampage caused by the antimalarial drug mefloquine hydrochloride.
Staff Sgt. Robert Bales said he doesn't know why he killed the innocent civilians.
The drug in question has been used by the U.S. military for three decades to treat malaria, but has been shown to cause neurological side-effects, ABC News reported.
The Food and Drug Administration (FDA) said the drug, also known as Lariam, can "occasionally" cause side effects such as mood swings and memory impairment.
An FDA report released by an unidentified pharmacist refers to a soldier who "developed homicidal behavior and led to homicide killing 17 Afghanis," after being exposed to the drug, ABC reported.
The study does not identify Bales as the subject, and cites that 17 civilians were killed, as opposed to the 16 reported in Bales case.
"Tens of millions of people take it. 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," Dr. Davis Sullivan, an infectious disease specialist at Johns Hopkins Malaria Research Institute.
The drug causes the dangerous side effects in about five to 10 percent of patients, and the label warns not to administer the medication if the patient had ever suffered a traumatic brain injury or seizure.
"This patient was administered mefloquine in direct contradiction to U.S. military rules that mefloquine should not be given to soldiers who had suffered TBI (Traumatic brain injury) due to its propensity to cross blood brain barriers inciting psychotic, homicidal or suicidal behavior," the anonymous report stated.
Bales confessed to the killings, avoiding the death penalty.
"What was your reason for killing them?" Col. Jeffery Nance asked Bales in court, the New York Times reported.
"There's not a good reason in this world for why I did the horrible things I did," Bales responded.
