I mean being happy is just a state of mind so I would say so, but being happy doesn't mean you're healthy in any way shape or form, albeit you probably knew that. If you want to think deeper about it it could be proposed that if you're depressed and you're able to delude yourself into thinking you're happy but actually aren't in your soul, and you can just tell that's true, then maybe the question could be more complicated than it would seem. That is the sign of greater mental torment and probably requires some searching within and not on internet forums.
Also do elaborate