you can do that, even the health bar given you are willing to put the time into it.
EDIT: actually the health bar might not be possible without extended functionality, since that requires being able to call specific sanity effects.
I did a simplified inventory system using sanity effects in the past, though that was on the experimental build which had extended functionality, and I got no idea if the vanilla game has that today.
If it does not, then you will have to use a more complex workaround, since the sanity effects are apparantly random or something, so you will need to call it a bunch of times or something like that to make it much more probable to occue. At least that's how I understood it, but I never used that method myself so dont take my word for it.
https://www.frictionalgames.com/forum/thread-22215.html