Mouse in a forced swim test

Depression is a debilitating and, typically, a chronic disease that affects about 264 million people, worldwide. It is a real illness that is a major cause of premature death in the world, especially among young men.

In the Porsolt or forced swim test mice or rats are gently placed in a small tank of water where they swim around to find a way out. When they understand there is no way out, they develop a floating posture. The rodents are naturally buoyant, so they don’t sink. Antidepressant drugs keep animals swimming and delay the onset of the floating posture. The animals treated with an antidepressant tend to swim around and explore the perimeter of the tank for much longer, sometimes, two to three times longer.

The forced swim test is a widely validated behavioural procedure for predicting antidepressant efficacy. It is highly reliable, very sensitive to antidepressant drugs across a wide range of different classes of medicines. It is the best model to test new potential antidepressant compounds,” explains Dr Bailey.

All the drugs that have a beneficial effect on depression in the clinic have shown exactly the same effect on the behaviour of rats and mice in this test. So, if a new molecule didn’t show prolonged swimming in rats and mice, it’s pretty certain that it wouldn’t attract the interest of industry for any further development because that test is such a gateway as an indicator of an antidepressant effect in humans,” elaborates Prof Stanford.

However, the forced swim test is rarely, if ever, used on its own to assess a potential new drug.

For more see

Last edited: 6 April 2022 09:25

Get the latest articles and news from Understanding Animal Research in your email inbox every month.
For more information, please see our privacy policy.