Robert T. Gonzalez in Salon:
To Freud, cocaine was more than a personal indulgence; he regarded it as a veritable wonder drug, and for many years was a huge proponent of its use in a wide array of applications. In a letter written to his fianceé, Martha, Freud wrote: “If all goes well, I will write an essay [on cocaine] and I expect it will win its place in therapeutics by the side of morphine and superior to it … I take very small doses of it regularly against depression and against indigestion and with the most brilliant of success.”
Freud published such a review, titled “Uber Coca” in 1884. Interestingly, Freud’s paper was one of the first to propose drug substitution as a therapeutic treatment for addiction. While replacing morphine with cocaine is something we now know to be counterproductive to recovery, the concept of substitution therapies persists to this day. (For a great overview of Freud’s relationship with cocaine, check out this post by Scicurious.)
More here.