ON A FRIDAY EVENING in November 2016, a 20-year-old medical student sat behind a mound of papers in a crowded college library, cramming for an upcoming examination on pathology and forensic medicine. The student, in his second year at DY Patil Medical College in Pune, was panicking about the amount that he had left to study. Later that night, he complained to a friend about the formidable syllabus. The friend gave him a small, white pill, insisting that it would help with concentration. He took it on Saturday evening and revised through the night, then took another one on Sunday evening, and studied all of the following night as well.

The student managed to make it to the examination hall on time on Monday morning, but blanked out when the question paper was placed in front of him. Despite having spent the weekend reviewing incessantly, there were substantial parts of the syllabus that he could not remember, and he was seized by another bout of panic. “His hands started trembling and it looked like he was having a fit. He submitted an almost blank sheet of paper and ran out of the examination hall,” a 22-year-old classmate of the student later recounted to me.

“He had to keep studying all the time,” his classmate said, adding that, in the lead-up to the exam on Monday, the student had grown “obsessive” and pored over his textbooks with an almost manic absorption. While revising the microscopic features of specimens that he would have to identify on slides in the examination, he revisited the same paragraph repeatedly to assuage his anxiety about having missed any minor details.