It would be difficult at best to identify the person who coined the term “Head Shrinker” for “Psychiatrist”. You probably would never find the person, let alone get them to admit it. But there it is… We would dare say that most people in the English-speaking world would use the term “Shrink” long before they would say, “I’ve been seeing a psychiatrist.”
According to “World Wide Words” website, the term is a bit convoluted.
“The original meaning of the term head-shrinker was in reference to a member of a group in Amazonia, the Jivaro, who preserved the heads of their enemies by stripping the skin from the skull, which resulted in a shrunken mummified remnant the size of a fist. The term isn’t that old — it’s first recorded from 1926.
All the early evidence suggests that the person who invented the psychiatrist sense worked in the movies (no jokes please). We have to assume that the term came about because people regarded the process of psychiatry as being like head-shrinking because it reduced the size of the swollen egos so common in show-business. Or perhaps they were suspicious about what psychiatrists actually did to their heads and how they did it and so made a joke to relieve the tension.
The earliest example we have is from an article in Time in November 1950 to which an editor has helpfully added a footnote to say that head-shrinker was Hollywood jargon for a psychiatrist. The term afterwards became moderately popular, in part because it was used in the film Rebel Without a Cause in 1955. Robert Heinlein felt his readers needed it to be explained when he introduced it into Time For The Stars in 1956: “‘Dr. Devereaux is the boss head-shrinker.’ I looked puzzled and Uncle Steve went on, ‘You don’t savvy? Psychiatrist.’” By the time it turns up in West Side Story on Broadway in 1957 it was becoming established.
Shrink, the abbreviation, became popular in the USA in the 1970s, though it had first appeared in one of Thomas Pynchon’s books, The Crying of Lot 49, in 1965 and there is anecdotal evidence that it was around earlier, which is only to be expected of a slang term that would have been mainly transmitted through the spoken word in its earliest days.”
Now don’t you feel better? It’s OK if you don’t. Just keep working on it.