Q: If people who spend all their time inside suffer from “agoraphobia,” do people who spend all (or much) of their time outside suffer from “claustrophobia”?
A: If “agoraphobia” is defined as fear of open spaces and “claustrophobia” as fear of closed spaces, then the two words would be opposites.
Those are the most common definitions in standard dictionaries, but some dictionaries have expanded on them to make the meanings overlap to a considerable degree.
Cambridge Dictionaries Online, for example, has the usual definitions, with “agoraphobia” defined as “fear of going outside and being in open spaces or public places” and “claustrophobia” as “fear of being in closed spaces.”
The online Oxford Dictionaries, however, defines “agoraphobia” as “extreme or irrational fear of crowded spaces or enclosed public places,” and “claustrophobia” as “extreme or irrational fear of confined places.”
We don’t see all that much difference between those Oxford definitions: “crowded spaces or enclosed public places” could well be described as “confined places.”
The Oxford English Dictionary (a different entity from Oxford Dictionaries online) expands the definition of “agoraphobia” further to include fear “of leaving one’s own home.”
The OED defines “agoraphobia” as “fear of entering open or crowded places, of leaving one’s own home, or of being in places from which escape is difficult.” It defines “claustrophobia” as “a morbid dread of confined places.”
So what do the two terms really mean? With dictionaries at odds, it’s your call. Pick whichever dictionary definition you’re comfortable with.
Getting back to your question, we might use those terms loosely to describe pathological fears that would keep people inside (“agoraphobia”) or outside (“claustrophobia”).
The noun “agoraphobia” was borrowed from the German agoraphobie, a term coined by the Carl Friedrich Otto Westphal in 1871, according to the OED. The word appeared later that year in the British journal Clinic:
“Agorophobia [sic].—With this name Westphal denotes a neuropathetic affection which he has recently occasionally encountered. Its most essential symptom, is a most acute anxiety or fear, experienced in open places, long passages, theatres, concert saloons, etc., with no other cerebral disturbance.”
Westphal, a neurologist, originally conceived of “agoraphobia” as simply the fear of large open spaces, though the word soon acquired wider meanings in psychiatric terminology.
The German psychiatrist formed it from the Greek agora (a public open space or marketplace) and –phobia (fear of).
“Claustrophobia” also has classical roots. It was formed from the Latin claustrum (confined space), the source of “cloister,” according to the OED.
The noun was coined by an English-born French medical professor, Benjamin Ball, in his article “On Claustrophobia,” published in the British Medical Journal in September 1879.
It’s interesting that in his paper, which was published shortly afterward in Paris under the title “De la Claustrophobie,” Ball compared the two disorders.
He characterized “claustrophobia” as “a state of mind in which there was a morbid fear of closed spaces … apparently different from, but in reality similar to, agoraphobia or the dread of open spaces.”
One last point. The pronunciation of “agoraphobia” has evolved in recent years for many speakers, with the secondary accent moving from the first syllable (AG-or-a-PHO-bi-a) to the second (a-GOR-a-PHO-bi-a).
The American Heritage Dictionary of the English Language (5th ed.) says in a usage note that the “variant has quickly gained acceptance” and is now accepted by almost three-quarters of its usage panel.
American Heritage now accepts both pronunciations. However, five of the other standard dictionaries we’ve checked list only the traditional pronunciation (AG-or-a-PHO-bi-a).
from Grammarphobia http://www.grammarphobia.com/blog/2016/02/phobias.html