Well, of course; that's the interest. With a standard mortgage you pay much more than you borrowed also. The big difference is that with a standard mortgage you get a lump sum up front and then pay it back bit by bit over time; with a reverse mortgage you get the money bit by bit over time and then pay it back in a lump sum at the end.
There are other differences, of course, like whether you can continue to get payments (i.e. borrow more money) during your lifetime even if it ends up with negative equity, whether that negative equity has to be paid in addition on sale, what the payback terms are, etc.
It's important to analyze the money flow to determine the interest rate and fee structure; yes, many scammers sell reverse mortgages that are very very costly in the end.
Josh