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Anti-Depressants for Retired Chimpanzees with PTSD

By Russell Tenofsky

A new study at the AAP Foundation, a Dutch rescue center for chimpanzees and other mammals from laboratories, has shown that anti-depressants used by humans can help chimpanzees in overcoming captivity-induced depression and trauma.

Aerial photo of the AAP Foundation, where researchers successfully used anti-depressants.

Despite having ample psychological stimulation, large spaces to roam, and a high-quality diet, scientists at AAP continued to note a steady decline in the “retired” chimpanzees’ mental health. The chimpanzees continued to display the classic rocking, pacing and self-mutilation behavior of captive animals, and that these behaviors even seemed to escalate over time.

In an effort to improve the lives of the chimpanzees, Dr. Godelieve Kranendonk, a behavioral biologist at the center, consulted Martin Bruene, a human psychology professor at the University of Bochum, Germany.

Professor Bruene prescribed an SSRI (selective serotonin reuptake inhibitor) for five of the center’s most affected chimpanzees. The SSRI was an anti-depressant similar to Prozac, which doctors often prescribe for humans to combat depression, anxiety disorder and obsessive-compulsive disorders.

A major improvement in how the chimpanzees acted and interacted with the other animals.In six to eight weeks, the animals began to show a change in their behavior, and after seven months the way in which the chimpanzees acted and interacted with the other animals improved tremendously.

“Suddenly, [the chimps] woke up,” said Dr. Kranendonk. “It was as if they were zombies in their enclosures and now they are happy, playing with each other. They are chimps again ­– that was really nice to see.”

Individuals who were previously anxious, screaming in terror and even eating their own vomit now engaged with each other. The results were “quite amazing,” said Professor Bruene. “I didn’t expect this to work this well. These chimps have served as laboratory chimps for many, many years and suffered psychological trauma. I wouldn’t expect a human [to recover] who has suffered a similar condition.”

Even though the anti-depressants improved the five chimpanzees’ psychological well-being, the brutal and agonizing life inherent to living as a chimpanzee in a laboratory has clearly taken its toll. One cannot erase the lifetime of trauma they have endured with a few short months of anti-depressants. Plus, no one knows what the lasting effects the anti-depressants will have – both in terms of side effects from the drugs themselves and what will happen once researchers take the chimpanzees off the medication.

“Once they have learned to be chimps again, they don’t need the medication anymore.”Nevertheless, so far, the results seem to be positive. Scientists gradually reduced the anti-depressants and they recorded no undesirable effects as of yet. One of the chimps even “decided” he didn’t want to take the medication anymore.

“It seems that while on the medication, the chimps learn to be chimps again,” said Dr Kranendonk. “And once they have learned that, they don’t need the medication anymore.”

Although this is a positive discovery, hopefully it will not promote the use of anti-depressants in masking the atrocities that scientists inflict upon chimpanzees and other animals slaving away in laboratories, zoos, and amusement parks.

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