Negra's caretakers describe her as socially isolated and withdrawn, and she assumed a depressed, hunched posture, much like you’d see in humans with depression.

Negra spent three decades in biomedical research labs. (Chimpanzee Sanctuary Northwest)

“She walked around with a blanket over her head, really isolating herself from the rest of the world,” says Ferdowsian.

Her study concludes that the behavioral changes Negra and many other chimps exhibited after their laboratory experiences were very similar to those seen in combat veterans suffering Post-Traumatic Stress Disorder (PTSD).

Proposed changes

Ferdowsian supports pending legislation in the U.S. Congress which would phase out experiments on chimpanzees and retire the apes to sanctuaries.

Rep. Roscoe Bartlett, a Maryland Republican, was a scientist before becoming a congressman and is now the main sponsor of "The Great Ape Protection and Cost Savings Act." He says Ferdowsian’s study confirmed what he already knew.

“That these animals aren’t the usual cow or pig or horse. They really are very different," says Bartlett. "They are primates and they have a huge brain and they have many characteristics similar to humans. It didn’t surprise me, but I was pleased to see the study.”

Foxie was used in hepatitis vaccine research. (Chimpanzee Sanctuary Northwest)