The question in the title presupposes that all Scottish Fold cats suffer from chronic pain but my research indicates that this is not necessarily true. Whether a Scottish Fold suffers chronic and severe pain depends on how the cat was bred. There are two ways to breed Scottish Folds. One way is acceptable while the other is not. There are strict guidelines from the cat associations on breeding this controversial cat.
Fold-to-fold breeding. Scottish Fold crossed with Scottish Fold
What is described as fold-to-fold breeding is irresponsible as one in three fold-ear kittens develop mild to severe vertebral deformities, prognathic (face deformity) and incapacitating joint disease caused by osteochondrodysplasia. It affects the cartilage throughout the body which is why the ears are flattened against the head and do not stand erect. The disease can be seen in 7-week-old kittens and is chronic (life long). It can cause crippling lameness and serious chronic pain. It is like osteoarthritis in humans. The cat might move slowly, be lethargic, avoid jumping, be tender to the touch, limp and so on.
This is why Scottish Folds can suffer permanent pain: it will be due to poor breeding practices.
Scottish Fold to American or British Shorthair breeding
In order to greatly minimise (as I understand it) the general joint disease caused by the presence of the mutant autosomal dominant gene that creates the folded ears, breeders cross Scottish Folds with a cat of a different cat breed such as the American and British Shorthairs.
Under these circumstances the symptoms of degenerative condition described do no appear or they occur in a milder form. My research informs me that this ensures that the joint disease does not affect the mobility of the cat or their general health. The source for this information is the Scottishfold.com website.
There appears to be unclear information on the internet on this topic. For instance the Universities Federation for Animal Welfare simply describes the Scottish Fold as suffering from osteochondrodysplasia without referring to the two alternative ways to breed this cat. Icatcare.com provides the same information which for me muddies the advice. Both these sites state that all Scottish Folds suffer chronically from osteochondrodysplasia which creates severe and painful arthritis. I am not sure that this is true for the reasons that I have stated above regarding different breeding methods.
Calls to stop breeding Folds
We don’t have information on how many Scottish Fold breeders follow good practice guidelines and do not breed fold-to-fold. The problem for breeders is that they might be encouraged to breed fold-to-fold to create a more purebred cat. The outcomes in respect of appearance are better but the health is not. There are calls to stop breeding this cat entirely because of this inherent health problem. Times change and people are more aware of and concerned about health issues in pedigree cats nowadays.
Treating the condition
There is no cure for congenital congenital osteodystrophy. Glucosamine might help but it seems that veterinarians may recommend euthanasia if the condition is severe and the cat is in bad pain.
I welcome input from breeders on this topic. More direct, first hand information is valuable. Please comment.