I'm no psychologist but I think claustrophobia can express itself in different ways in different people - if it's the enclosed spaces in caves that make you fearful/anxious, it's a claustrophobic reaction. You wouldn't necessarily also have to have the same reaction in e.g. an elevator.

> claustrophobia can express itself in different ways

Too right. I'm a reasonably experienced cave diver, and regularly dive in a system of 11km of intersecting fully-underwater tunnels, with the single entry/exit being a small pond, a few feet across, in a small, underground air-filled cave. I'd typically go 700-800 meters out, with a dozen navigational decisions along the way (left? right? straight ahead?), then have to reverse all that to get back out. But a few years ago I had an MRI, where you're wheeled into a narrow metal tube, on your back, with your arms pinned to your sides, with the tube an inch away from your face. Result: GET ME OUT!! GET ME OUT!! I had to be wheeled back out & take a break, before I could grit my teeth and try again. I absolutely hated it. I told them I was an active cave diver, but I don't think they believed me :-)

My personal experience is that I never experienced claustrophobia in normal conditions (lifts, tunnels) but I did while scuba diving in the dark.

There are degrees to these phobias, of course. One can find a four story roof acceptable but a ten story roof terrifying. Or a speech in front of twenty easy but one in front of 1000 paralyzing.

Scope doesn't change the phobia.

Of course. Caves aren't designed by people for people, so there are surprises there.

I haven't thought that it's a big deal until actually having to lead into a pretty tight passage without prior information about it.

Cavephobia! ;-)

(as others point out, it's probably the same)