Psychiatrists are commonly referred to as shrinks due to the historical likening of a psychiatrist's practices to the practice of primitive tribes preserving and shrinking the heads of their enemies. The slang term "shrink" evolved from the longer term "headshrinker."
"Shrink" originally referred mainly to psychiatrists, but is now used in reference to numerous professions having to do with counseling or psychotherapy. Though "shrink" is not always used in an intentionally negative way, the likely background of the word consists of negative attributes in the realm of magic, shamanism, spiritual ritualism and primitive tribal practices. "Shrink" can be viewed as greatly minimizing the knowledgeable practices and notable qualifications of a psychiatrist.
Describing a psychiatric professional as a shrink implies a reductive form of thinking. Reductive thinking focuses on the root cause, believing that having enough information leads to discovering the root cause of a person's problems. A positive implication of the term shrink is the idea that psychiatrists may help minimize, or shrink, a client's personal issues. In recent times, the term is often used respectfully and with no negative implications. Overall, calling a psychiatrist a shrink may be derogatory, but is more likely to be used as a term of endearment.