25th Jul 2023
The Animals in Science Committee (ASC) has published a report on the use of the forced swim test (also known as the FST or Porsolt Swim Test) in research, in which it recommends use of the FST under specific research purposes, where these are robustly justified and scrutinised.
The report follows a review initiated by the UK Home Office, in which the ASC was asked to advise on the evidence of alternative methods and appropriate justification for the use of the FST. In addition, the ASC was asked how principles to replace, reduce and refine the use of animals in research (the 3Rs) should be applied regarding the FST.
As highlighted by Understanding Animal Research, the FST is a behavioural test which is mostly used to assess the efficacy of potential antidepressant treatments. It involves putting a rat or mouse into a small tank of water, from which it cannot escape, sometimes for up to 5-6 minutes, after which it is lifted out.
To help inform their review, the ASC issued a wide call for evidence, including from stakeholder organisations, and the BNA responded on behalf of the neuroscience community.
The BNA is committed to openness on the use of animals in research and is a signatory of the Concordat on Openness on Animal Research in the UK. We also strongly endorse the principles of the 3Rs, encouraging replacement, reduction and refinement where appropriate for neuroscience research. Within that context, in our response to the ASC we highlighted that there is sufficient evidence to justify the continued use of the FST in specific areas of neuroscience research, where this is shown to be valid and where it cannot be replicated by alternatives.
Within neuroscience research, the FST plays an important part in research for new treatments to improve mental health, during the preclinical development of antidepressant drugs. In some research projects, the FST is also used to help to provide insight into the neural mechanisms at play in behavioural responses to stress, which is beneficial for research into stress and psychiatric disorders relating to stress.
We believe it is important for neuroscientists to be alert to all possible refinements of, and replacements for, the FST that could reduce the need for it to be used, though agree with the ASC finding that at present current suggested alternatives are not reliable, reproducible and accepted.
The ASC has recommended that the FST should not be used as a model of depression or to study depressionlike behaviour (including in the phenotyping of genetically altered mice) or for studies of anxiety disorders and their treatment. It also recommends to potential licence-holders that an applicant should ensure the parameters of the FST are optimised so that the most refined protocol is being used, commensurate with the power of the test being adequate to meet the objectives of the study, and that details of how the FST is conducted should be recorded and reported in publications. The BNA notes that this would also improve research credibility, and welcomes this advice.
The ASC also recommends that further research should be conducted into non-animal methods for studying depression, antidepressants and other areas of research where the FST is currently used. Alongside the report, Prof David Main (chair of the ASC) has written to government ministers to highlight that while there is still a requirement to use animals in science where no validated alternative methods are available, there should also be a drive to lead the development and implementation of new non-animal technologies and new approach methodologies. To help support this drive, Prof Main has recommended that ministers consider re-locating the animals in science policy function away from the Home Office to the Department for Science, Innovation and Technology.
