Pharma companies face scrutiny over controversial Forced Swim Test

Small animals are administered doses of experimental drugs and then dropped in cylinders of water so that researchers can measure how long they struggle

Hyderabad: The controversial Forced Swim Test (FST), which involves drowning small animals such as mice, guinea pigs, rats and hamsters in inescapable water containers to understand depression in humans, a practice which is widely followed even today by pharma companies, may soon become a thing of the past.

A few days ago, the Pharmacy Council of India (PCI) has directed its member constituents and pharma companies to review and take action on the continued use of this experiment, following a series of study papers presented by PETA over the inefficacy of such tests.

In the forced swim test, researchers put mice, rats, guinea pigs, hamsters, or gerbils in inescapable containers filled with water. The panicked animals try to escape by attempting to climb up the sides of the beakers or even diving underwater in search of an exit. They paddle furiously, desperately trying to keep their heads above water. Eventually, they’ll start to float.

In the 1970s, a researcher Roger Porsolt made this test famous as the Porsolt Test or Behavioral Despair Test. He found that rats that had been given human antidepressant drugs would struggle and swim for longer than other rats, and he concluded that those who swam for less time were depressed.

Even today, after four decades after Porsolt’s experiments, laboratories in universities and pharmaceutical companies utilise this test. Small animals are administered doses of experimental drugs and then dropped in cylinders of water so that researchers can measure how long they struggle.

According to PETA studies, the forced swim test doesn’t accurately predict whether a drug will work as a human antidepressant. It yields positive results for compounds that aren’t prescribed as human antidepressants, such as caffeine. Importantly, antidepressant compounds that might work in humans may be mistakenly abandoned based on the test.

The bottom line is that the forced swim test is bad science. These experiments do nothing more than terrify animals and delay the development of new effective treatments that are so desperately needed, PETA in its studies said.

According to the animal welfare association, several government agencies, universities and world’s top pharma companies have already pledged to not to permit/ conduct/ fund forced swim tests.

Highlights of FST

• Small animals dropped inescapable water tanks to put them under pressure/stress
• Animals try to cope by trying to escape, swim, climb to escape
• Over time, attempts to escape decrease and they become immobile
• Researchers score the time the animal spends floating with minimal effort
• Porsolt displayed that animals on antidepressants struggle longer and spend less time floating
• This was taken to mean that longer swimming times indicate less depressed animal
• It was believed that antidepressants caused this behavior change.
• Animals who gave-up and only floated were believed to be in despair