Most runners have heard the story of how superstar marathoner Alberto Salazar over-trained and over-raced himself into depression, and how he briefly “recovered” by taking selective serotonin reuptake inhibitor (SSRI) drugs.

What is it about these “feel-good” drugs – sold under the commercial names Prozac, Paxil, Zoloft, etc. – that makes them improve performance?

In “Runner Meds,” [...]