The central event in “The Mushroom Cure” is Strauss’s encounter with Grace, a young woman from Kansas – a grad student in psychology, no less — whom he meets while hawking his stand-up set in the neon wilderness of Times Square. (Her name may seem too on the nose, but Strauss says he’s changed no one’s name in his narrative.) What starts as a one-night stand blossoms into something more. And when Grace tells him about how her own experiences with psychedelics helped her overcome a bout of depression in her teens, Strauss’s interest (earlier spurred by internet research) into the salubrious benefits of psilocybin really takes off.