The forced swim test is a behavioural test which involves placing a rat or mouse into a small tank of water from which it cannot escape and measuring the time spent swimming/not swimming. All clinically used anti-depressant treatments increase swimming behaviour in the forced swim test.
Despite its widespread use, the forced swim test is highly contentious and has come under considerable scrutiny, in part due to its severity and effect on animal welfare. There are also concerns about its scientific utility. The latter includes the lack of neurobiological correlation between the behaviour of animals and the effects seen in humans, and its inability to model the speed at which an antidepressant begins to take effect following regular dosing.
A position paper on the use of the forced swim test and its alternatives is in preparation and will be published shortly.
Recommendations on the use of the forced swim test
In 2021, we collaborated with the MHRA to publish recommendations on the use of the forced swim test, to clarify the regulatory perspective on the use of this test. The paper outlines what the forced swim test can and cannot be used for (i.e. it is not a model of depression but may have utility as a screen for the development of antidepressant drugs); opportunities to refine the test from an animal welfare perspective; and calls for investment into alternative approaches.
