Lab chimps successfully treated with anti-depressants
|The chimps, like Tomas, were all disturbed|
A study has shown that anti-depressants can be used to help former lab chimps combat depression and trauma.
Researchers say that the treatment should be considered for hundreds of other chimps that have been used in scientific research.
The finding comes as a US funding body thinks about retiring the more than 300 chimps it uses for medical research.
The study was presented in Boston at the at the American Association for the Advancement of Science (AAAS) meeting.
Dr Godelieve Kranendonk, a behavioural biologist leading the study at AAP, a rescue centre for animals in the Netherlands, told BBC News that the results had been astonishing.
"Suddenly, [the chimps] woke up. 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," she told me.
AAP is a rescue centre for Dutch chimps and other mammals that have been used in scientific research.
Many animals emerge from their time in laboratories depressed and traumatised. Having been confined for 15 to 20 years as lab animals, they have lost their ability to play or relate to other chimps. Instead, they spend their time in brooding isolation and sometimes eat their own vomit.
The chimps often repeatedly rock back and forth, pace back and forth and pull their own hair.Playfulness restored
Staff at the AAP sanctuary care for the animals until they die. They try to rehabilitate them so that they can live out their remaining years happily.
The chimps are fed a good diet of vegetables, have toys and plenty of space in which to play. But Dr Kranendonk found that the abnormal behaviour actually increased. It was as if the animals did not know how to cope with their new found freedom.
Dr Kranendonk decided to consult Martin Bruene, a professor of human psychiatric disorders at the University of Bochum, Germany. He prescribed a course of anti-depressants for five of the chimps.
All the animals had been used in medical experiments and were infected with Hepatitis C. "Willy" showed the least abnormal behaviour. "Tomas" and "Zorro", on the other hand, would spend a third of their waking hours eating their own vomit.
"Iris" had lost so much weight from vomiting when she first came to the sanctuary that the staff thought she would die.
The most troubled though was "Kenny", a small chimp who was constantly anxious that the others would attack him and spent much of his time screaming in terror.
The chimps were given SSRI (Selective Serotonin Reuptake Inhibitors), which is a class of anti-depressant similar to Prozac and is used to treat human patients for depression, anxiety disorder and obsessive compulsive disorder.
After six to eight weeks, the animals behaviour started improving. The abnormal behaviour declined and the chimps began to play together. After seven months, there was a vast difference.
Kenny responded best of all to the treatment. He is now the clown of the group, entertaining the others and initiating play.Long-term prognosis
Prof Bruene said that the results were "quite amazing". More