Lab chimps successfully treated with anti-depressants

Tomas (©AAP, Petra Sonius) The chimps, like Tomas, were all disturbed

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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.

Pallab Ghosh reports from the AAP sanctuary

Prof Bruene said that the results were "quite amazing".

He said: "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] that has suffered a similar condition."

After decades of being research animals, the chimps unsurprisingly looked weary and dishevelled, even after their anti-depressant treatment.

Gone was the energy and playfulness that one sees in wild chimps. But they had an engagement that was absent from other chimps in the sanctuary that had not received the medication.

Kenny, for example, came to the front of his cage to show me the carrots he was about to eat. Then, after noticing that I was taking what he may have though to be too great an interest in his dinner, he scuttled off quickly, flashing a suspicious glance as he clutched his carrots tightly to his chest.

And after dinner, Iris and Zorro played together affectionately, even exchanging a kiss.

The big question though is whether the effect lasts when the chimps are taken off the medication. The early indications are promising. The medication has been steadily reduced and there has been no adverse effect on the chimps' behaviour.

Kenny himself decided that he did not want to take the anti-depressants anymore. His clownish behaviour has continued.

"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 any more."

American decision

The result comes at a time when the world's largest user of chimps in medical research is considering retiring more than 300 of its animals.

A recent scientific review for the US National Institutes of Health concluded that there were alternatives to using chimps in many cases, and that the greater suffering these higher animals experienced dictated that nearly all the animals in NIH-sponsored research should be retired.

An expert group of scientists has suggested that the chimps should be sent to a national sanctuary which has been dubbed "Chimp Haven". The 80-hectare (200-acre) site in Louisiana was opened in 2005 as a retirement home for research chimps that were no longer needed.

The proposal from the NIH committee is the latest step in a shift away from using chimps for medical research in the US.

But the experience of Dr Kranendonk and Prof Bruene suggests that simply releasing the chimps into a large open air sanctuary will not be enough. Unless the animals are properly supported, Chimp Haven may well turn out to be Chimp Asylum.

Prof Bruene believes that the NIH should consider giving their animals anti-depressants if they show symptoms of depression before releasing them. He thinks their conditions are treatable and that, as our closest relatives in the animal kingdom, they deserve proper psychiatric care.

"It could be a good model for other facilities to at least try and improve their conditions," he said.

Research on great apes in the UK was banned in 1986.

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  • rate this

    Comment number 77.

    Reading some of the comments I can see the Nazis could of learned a thing or two from animal rights activists.

    The sickening hypocrisy of these people - Torturing and killing humans is fine if they are offended by them but animals including vicious predators that would eat their face for lunch are sacred
    The irony here is that the drugs have been tested on humans before being given to the animals

  • rate this

    Comment number 76.

    I see, so now drugs are tested on humans before being used to treat animals.
    I wonder how many of these Chimps will go on to develop psychological conditions, maybe one or two will grab assault rifles and shoot up the local Zoo.

    I guess big Pharma are running out of schoolchildren to dope up but hopefully GP's will still get the same perks prescribing for Chimps as for pushing these drugs on us.

  • rate this

    Comment number 75.

    72. Graphis

    "The public can volunteer for trials, and are paid. Why not prisoners?"

    I have no problem with this. However, it's a very different idea to what has been suggested below (an idea I have unfortunately heard mentioned before):

    59. "Our prisons are over flowing with evil people who should be used in testing. The more severe the crime, the more severe the testing should be"


  • rate this

    Comment number 74.

    There was a time when I would never have felt like this, but if I contracted HepC I would honestly rather die than be cured as a result of even one deliberately infected primate's suffering. We're supposed to be better than this, aren't we?

  • rate this

    Comment number 73.

    I would like to see a chimp being offered homeopathy and hopefully he'll smash the place up, causing a huge leakage of dangerous chem...I mean water.

  • rate this

    Comment number 72.

    62. Nick
    "As for testing on criminals, I find the idea abhorrent."

    Certainly, if its mandatory. But perhaps some prisoners might be offered the opportunity to participate in tests, in exchange for a reduction of their sentence or other privilege?

    The public can volunteer for trials, and are paid. Why not prisoners?

  • rate this

    Comment number 71.

    Remember AIDS? It killed and there were no treatments. We now know the cause (HIV) and have effective medicines. Animal studies were important in that. Thankfully use of chimps in research is waning but what of the chimps to be retired? Institutionalised humans struggle in the wider world and antidepressants help. It seems preferable to treat the chimps in a similar way rather than put them down.

  • rate this

    Comment number 70.

    It's way past time to get all chimpanzees out of labs. Knowing all we know about their complex emotions, their lack of necessity for medical research--and the extreme suffering they go through in labs--we can't keep even one chimpanzee in a lab cage for any reason.

  • rate this

    Comment number 69.

    65 David Traynier - I think your definition of "evil" is rather loose. As humans, we currently kill plenty of other people just because they worship the wrong god, are the wrong colour or happen to live near some people that might be terrorists.
    At least this time we're harming something for a benefit!

  • rate this

    Comment number 68.

    67.Isis B

    It is not a good thing so much as one of the least bad methods we currently have - but other better methods are being rapidly developed/placed into useage.

    Many drugs pass animal models fine then harm humans - how many that harmed animals/didn;t work in them & got no further might have worked well in humans...???

  • rate this

    Comment number 67.

    Using animals to test for drugs that improve the quality of our illnesses is a good thing. Horrible it may be, however, the outcome is less people dying from problems that can be cured. I have had depression for 19 years, it's not pleasant. And if we can give something back to the animals that are helping our lives then we should do so.

  • rate this

    Comment number 66.

    For the record vivsection in the sense of those shocking photos we;re shown by activists does not happen any more in the UK.

    Also whilst too many animals are still experimented on the nos are at their lowest for decades & coming down faster & faster over time.

    "Lab in a chip", cell lines et al are all proving much better models than animal ones.

  • rate this

    Comment number 65.

    This really is an illustration of the banality of evil.

    Animal testing rests on the premise that it is acceptable for one sentient species to use another as a means to its own ends. The justice of this premise is illustrated by a simple thought experiment: to imagine ourselves as the species on the other end of the equation.

    It's a big universe out there.

  • rate this

    Comment number 64.

    Born cynic. Like a vegetarian who eats a steak because the cow's already dead? I wasn't condoning criminal behaviour. I just don't agree with you that we should experiment on prisoners.

  • rate this

    Comment number 63.

    #57 - Your logic is idiotic. To say if you dont like animal testing dont benefit from it. Wel whats a greater insult to have let the animals suffer and then not use what was learnt, even conc camp victims would not say dont use what you learnt from us. To defend the hideous people who dont respect human life and comit unspeakable crimes is truly frightening because you condone their actions.

  • rate this

    Comment number 62.

    Nobody likes animal testing and that includes those performing it. Unfortunately however, it is currently the safest and best way to determine the safety of new drugs and to gain understanding of the biological systems involved. As for testing on criminals, I find the idea abhorrent. I know internet discussions tend toward comparisons with the Nazis, but on this occasion I find it appropriate.

  • rate this

    Comment number 61.

    Stop using the animals. Instead use people like those responsible for Jamie Bulgers death.

  • Comment number 60.

    This comment was removed because the moderators found it broke the house rules. Explain.

  • rate this

    Comment number 59.

    Totally agree with you Sproutaholic! Our prisons are over flowing with evil people who should be used in testing. The more severe the crime, the more severe the testing should be. This will stop the cruel torture of innocent animals who have done NOTHING wrong and also serve as a deterrent to criminals! 2 for the price of 1!

  • rate this

    Comment number 58.

    The use of animals for testing is something that I find evil. Upsetting to the extreme even if animal testing has reduced in recent years.
    However, would I decline a life saving drug or operation for myself or children because it was initially tested on animals?
    The answer is a 'no brainer'. Of course I wouldn't and I suspect few would decline - including the 'Animal Rights' extremists.


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