So what happens is that medication patents are for a set period of time. Pharm companies can get their patent extended if they add an indication later on. So Pharm companies purposely hold on to indications so they can extend the patent later on. The flip side is that it is expensive to get a new indication, and frequently not worth the cost to the Pharm company.That being said, some of the most well know benefits of certain meds are technically off label usage. The problem here is that they market the drugs for said usages. Very unethical and illegal to boot.