NHMRC releases position statement on controversial Forced Swim Test

Animal-Free Science Advocacy

Funding agency declares test is not justified.

The National Health and Medical Research Council (NHMRC) has released a policy statement on the Forced Swim Test (FST), a behavioural despair test in rodents used to screen anti-depressant drugs, which involves placing a mouse or rat in a beaker of water and forcing them to swim, offering no escape route. The NHMRC states that ‘When the scientific validity of this procedure for the proposed research is not supported by robust evidence, the use of the forced swim test in rodents cannot be justified in accordance with the Australian code for the care and use of animals for scientific purposes and must not proceed’ and specifies that the FST in rodents must not be used in any new projects as a model for depression in humans, to study depression-like behaviour.

Originally designed in the 1970s, the cruel and outdated FST has faced increasing scrutiny over recent years and as such its use has now ended in many pharmaceutical companies and research institutions around the world. A 2022 NSW Inquiry into animal experimentation called for a rapid phase-out of the FST, the Inquiry committee concluding that the harm caused by this research is greater than the human health benefits gained. Its use it not a requirement for regulatory approval of anti-depressant drugs.

Experts reason that floating is more likely to be an indication that animals are learning, conserving energy, and adapting to a new environment than a sign of depression. Whilst depression is a chronic, relapsing disorder, the mood of an animal can change when the test in complete and does not represent the human condition. Immobility in animals may be prevented by a drug within 24 hours, whereas there is a therapeutic lag in humans, further evidence of the futility of the test.

The field of mental health needs viable, basic and translational research and by continuing to use a test as scientifically flawed as the forced swim test there is a great risk that data obtained is unreliable and could indeed lead to misleading results and ineffective treatments. Relevant alternatives to the FST include testing on human platforms. For example, novel compounds can be identified using mathematical or computer modelling of human systems, or by drug repurposing programs. These compounds could be tested on human tissues or cells using advanced in vitro methods, such as in organoids or microfluidic systems. Epidemiology is another valuable tool for understanding how to prevent and treat human depression.

Animal-Free Science Advocacy supports the position adopted by the NHMRC and urges the funding body to support a full prohibition of its use. To ensure the test in rapidly phased out, Animal-Free Science Advocacy calls for:

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