Popular opinion is that cribbing is incureable, and maybe it is, but I have had great success with my OTTB, and based on that I think it can be at least greatly reduced.
My OTTB when I got him was a constant compulsive cribber to the point that he had no top teeth. I put him 24/7 in an open paddock but he would just find the nearest fence post and spend hours cribbing. He also had frequent bouts of what we initially thought was colic but then came to suspect was stomach ulcers. Apparently about 90% of ex-racehorses in Australia come off the track with stomach ulcers. So we didnt bother testing we just went ahead and treated him for ulcers.
After we treated the stomach ulcers he stopped a lot of the cribbing but was still doing it sometimes. I tried the pastes, sprays etc - didnt work. Also electric tape etc, he then started cribbing by sitting down and latching onto a chunk of grass!
I was very reluctant to use a collar as I thought it would be cruel BUT when I tried it, it worked immediately. Yes you have to put it on very tight and it will rub. What I did was buy two very different types- a nutcracker type and a leather amish design. So they rubbed in a different spot and I would switch then around to give each spot a rest. The first time he had it on he was like a junkie robbed of his fix, he was in a filthy mood (not like him at all) for about a week but he got over it.
After about 4 months I tried taking it off and found that as long as he is not stressed he will now go for months without cribbing. When I had to put him at a friends place in an emergency he started cribbing again so the collar went back on. When I brought him home, took it off after a few days and he was fine.
Last two weeks I have been very busy at work so he hasnt had the usual attention. Surprise! he started cribbing again. So he has the collar back on now, hopefully just for a week or two.
So within the space of a year he has gone from constant cribbing to going for up to three months without cribbing at all.
So Id say: 1. suspect stomach ulcers
2. avoid stress, boredom and confinement for the horse.
3. Try using a cribbing collar just to get him out of the habit, he may not have to wear it forever.