Animal rights groups have called on Edinburgh University to stop subjecting animals to a “near drowning” test during its research into antidepressants, arguing the experiment lacks “scientific value” and is “cruel and unreliable”.
People for the Ethical Treatment of Animals (Peta) says the university uses a “widely discredited forced swim test” that “torments” small mammals by forcing them to keep swimming in inescapable beakers to prevent themselves from drowning.
Peta claims animals have drowned during experiments and is calling on Edinburgh University to follow the example of 14 organisations and two universities – including Kings College London – which have banned the forced swim test.
It is backed by Animal Aid which describes the experiment as “outdated” and “chilling”.
Edinburgh University said in response, however, that it only uses animals in research “where there are no alternatives and their use is justified on scientific, ethical and legal grounds”.
Forced swim test
According to a group called Understanding Animal Research (UAR) the forced swim test, aka FST or Porsolt swim test, is a behavioural test which assesses the “efficacy of potential antidepressant treatments”.
During the experiment mice, rats and gerbils are placed in small tanks of water and forced to swim to keep from drowning.
Water is heated to between 25 and 30 degrees centigrade to ensure animals do not develop hypothermia. After a few minutes of swimming around and trying to climb out of the tank, the animal stops trying to escape and instead floats in the water, moving occasionally to keep floating.
UAR says the length of time the animal was active and then floating (immobile) in the water is recorded. Additional behaviours including swimming and climbing may also be noted.
“Mice and rats are naturally buoyant and each can stay afloat for up to three days so there is no realistic chance of them drowning in 5 to 6 minutes in warm water,” UAR told The Ferret.
Its fact sheet on the experiment explains: “Antidepressants make stressed animals move more than they would if they had not been given an antidepressant, so if the animal has been given an antidepressant treatment prior to the test it will spend more time swimming and less time floating.
“Animals that have not been given an antidepressant treatment (known as ‘controls’) or animals given a treatment that does not have antidepressant properties will spend less time swimming and more time floating.”
UAR claims that by comparing the swimming and floating times of the dosed animals and the control animals, researchers can tell whether or not a potential new antidepressant is likely to be an effective treatment in depressed patients. If a potential treatment works in these animals, it can then go on to further stages of testing, UAR says.
It added: “There’s an acute need for new depression treatments as it’s estimated that up to 30 percent of patients don’t respond to any therapy we currently have . While new drugs are unlikely to be the sole ‘cure’, they will almost certainly be part of a multi-pronged solution.”
However, Peta says the test is “absurd” and has been criticised by scientists who argue that floating is not a sign of depression or despair, but “rather a positive indicator of learning, saving energy, and adapting to a new environment”.
Peta’s science policy manager Dr Julia Baines, said that repeatedly subjecting mice and rats to a “near-drowning experience teaches us nothing about the complexities of human depression and doesn’t tell us what drugs will be effective antidepressants in humans”.
She added: “The University of Edinburgh first learned from Peta in 2019 that the test not only lacks scientific value but also torments animals. However, the university only went as far as to say that its “animal welfare and ethical review body will continue to keep this issue under review, as it does for all procedures”.”
Baines urged Edinburgh University to “focus instead on advanced, animal-free research methods that might actually help human patients”.
Animal Aid also criticised the experiment and said it was “astonishing that some researchers persist in out-dated and archaic animal experiments, including the forced-swim test”.
“To place small animals into water-filled beakers, from which they have no hope of escape is, quite frankly chilling. It tells us nothing about human depression,” a spokesperson for Animal Aid added.
They continued: “We would urge the researchers still conducting these terrifying and irrelevant tests to stop, as many companies and universities already have. These tests should be banned, not only for the sake of the animals they harm, but for the sake of robust science.”
In reply Edinburgh University defended the FST and said animal welfare was a priority. It said all its animal research is overseen by an Animal Welfare and Ethical Review Body (AWERB), a legal requirement under the Animals (Scientific Procedures) Act 1986.
In addition to the AWERB, the university has a “seperate 3Rs committee” which advises on the reduction, refinement and replacement of animals in research.
Animal testing ‘justified’
A University of Edinburgh spokesperson told The Ferret: “We use animals in research only where there are no alternatives and their use is justified on scientific, ethical and legal grounds.
“All such work is carried out in compliance with the law under licences that are reviewed by a local committee (the Animal Welfare and Review Body, or AWERB), who assess if the benefits of the research outweigh any potential cost to the animals concerned.
“We regard animal welfare as a priority and we continually review the procedures used in our facilities to ensure we implement the most up-to-date measures to reduce, refine and replace the use of animals wherever possible.”
Last December Peta obtained video evidence of the FST at Bath University. It has urged the academic institution to end the experiment.
Bath University declined to comment.
Cover image thanks to iStock/unoL
This story was updated to add the following paragraphs at 14.50 on 15 January 2021 –
UAR said: “Mice and rats are naturally buoyant and each can stay afloat for up to three days so there is no realistic chance of them drowning in 5 to 6 minutes in warm water.
“There’s an acute need for new depression treatments as it’s estimated that up to 30% of patients don’t respond to any therapy we currently have . While new drugs are unlikely to be the sole ‘cure’, they will almost certainly be part of a multi-pronged solution.“