Though some of Freud’s major biographers — most notably the British historian Peter Swales — remain convinced of the influence of the drug on Freud’s entire edifice of psychoanalytic thought, most agree with Markel’s conclusion that he completely stopped 12 years of what Markel calls “compulsive cocaine abuse” in 1896, just as he was beginning to formulate the concepts that laid the groundwork for his historical legacy. During the period of Freud’s addiction (or, at the very least, abuse), he wrote frequently about cocaine, making plenty of references to its debilitating effect on his clarity of thought. But the drug is rarely mentioned after 1896. That was the year in which two major events occurred in Freud’s life. The first was the publication in a French medical journal of his influential article “The Aetiology of Hysteria,” in which the word “psychoanalysis” is used for the first time; the second was the death of his father. Freud was no doubt influenced by having been close witness a few years earlier to the anguished death of one of his dearest friends, the accomplished young phsyiologist Ernst von Fleischl-Marxow, whose morphine addiction Freud had tried to treat with cocaine, with disastrous results. As Freud wrote almost three decades later, “the study on coca was an ­allotrion” — an idle pursuit that distracts from serious responsibilities — “which I was eager to conclude.”

Markel, a professor of medical history at the University of Michigan who has also done clinical work involving the treatment of addicts of all sorts, has instructive ways of explaining Freud’s method of turning away from what he had by then realized were the deleterious consequences of drug use. “Most recovering addicts,” he writes, “insist that two touchstones of a successful recovery are daily routines and rigorous accountability.” Around 1896, Freud began to follow a constant pattern of awakening before 7 each morning and filling every moment until the very late evening hours with the demands of his ever enlarging practice (he was soon seeing 12 or more patients per day), writing, lecturing, meeting with colleagues and ruminating over the theories he enunciated in such articulate literary style. Markel concludes: “It appears unlikely that Sigmund used cocaine after 1896, during the years when he mapped out and composed his best-known and most influential works, significantly enriched and revised the techniques of psychoanalysis and . . . attempted to ‘explain some of the great riddles of human existence.’ ”

As Markel shows, the addiction of Freud’s contemporary William Halsted played out very differently. Halsted was a consummately brilliant and flashy surgeon who had captained the Yale football team and then gone on to medical training in New York, where he soon established a reputation not only for his operative skills and speed but for the outgoing personality that distinguished him as a bon vivant and hail-fellow-well-met. In 1884, while working mainly at Bellevue Hospital, he and a small group of rising young doctors began to self-experiment with cocaine, in order to develop techniques that would permit surgery on the extremities and other areas whose nerve supply could be blocked by direct injection of the drug. Unaware of its dangerously addictive qualities, each of the young men gradually fell under its diabolical spell.