For the past few decades, scientists studying candidate antidepressant drugs have had a convenient animal test: how long a rodent dropped in water keeps swimming. Invented in 1977, the forced swim test (FST) hinged on the idea that a depressed animal would give up quickly. It seemed to work: Antidepressants and electroconvulsive therapy often made the animal try harder. The test remains popular, appearing in about 600 papers per year.
But researchers have recently begun to question the assumption that the test really gauges depression and is a good predictor of human responses to drugs
