More than 21 million people worldwide suffer from schizophrenia, a profound mental illness that interrupts thinking, language and perception. Quite a few schizophrenic people experience delusions and hear voices. Many of the disease’s symptoms stem from faulty communication between brain cells. And, for decades, scientists have searched for a cure in the brain.

Now researchers say they’ve discovered that the way to heal schizophrenia might be through the gut. There’s an ecosystem of bacte