Why did Whitney Houston refuse to go on talk shows in the 80s and early 90s?

She went on Letterman and Joan Rivers in 1985 at the very start of career but never came back until the late 90s.It seemed like you only heard about her when she released new music but for the most part she was reclusive. People talked about her a lot because she was a huge star, but she never went on any shows to talk about herself. As a result rumours about her were started regarding her sexual orientation and all sorts of things, and she wasn't able to defend herself from these rumours because she never went on Letterman until the late 90s. Why was she so reclusive even before she got addicted to drugs?