Can it be destructive to the horse? The answer is yes.
Cribbing is a vice much like a human biting their finger nails. It can lead to destruction of the horse’s living quarters, it can lead to enamel wear of the incisors and in some cases to negative intra-abdominal pressure that in some cases leads to epiploic foramen entrapment where a piece of bowel becomes trapped in surrounding organs – this can require surgical intervention. Some believe this is a learned behavior but I have encountered horses that have started this vice without being exposed to another “cribber”. Another theory is that the horse cribs in an effort to overproduce saliva that contains bicarbonate to swallow in order to buffer stomach acid during stress, empty stomach, or gastric ulcers.
As for treatment, it is difficult to “treat” a cribber once the habit is started. There are several treatment options that attempt to correct the issue but when there are several treatments it’s usually because none work 100% of the time, on all horses. Some options are: cribbing collars that attempt to prevent the horse from being able to suck air, slow feeders that attempt to keep the horse busy thus keeping its mind busy, there are also bitter tasting substances that are painted on surfaces in an attempt to thwart the cribber with a foul taste. Another answer is to keep the horse out in a pasture where there is nothing to crib on and hopefully the horse is too busy eating all day that they forget to maintain their addictive habit.