Ctrl - F led me to find this as the only time schizophrenia is mentioned in the article.

Heath had already developed a particular interest in schizophrenia, which he viewed as the single greatest challenge in mental health, affecting roughly 2 percent of Americans. He noticed that such patients seemed largely unaffected by either lobotomy or topectomy; since these procedures targeted only the most immediately accessible part of the brain, the cortex, he concluded that their symptoms must be more deep-rooted.

So Heath began his investigations of the subcortex (literally, ‘the part below the surface’). And one particular area—the septal region—appeared particularly promising. When it was damaged or destroyed in cats and monkeys, they started behaving in a startlingly similar fashion to people with schizophrenia: their emotions were dulled, they lost their ability to experience pleasure (a phenomenon known as anhedonia), and they generally seemed to be removed from reality.

This reinforced Heath’s burgeoning conviction that schizophrenia was a biological, not a psychological, problem: something “dependent upon a defect in basic machinery, rather than a complication of environment," as he would later write. By implanting electrodes into the deepest parts of the brain, he could not only examine how this machinery operated, but also—he hoped—jolt it back into life.