I personally use sick time for mental health days, my sm allows us too. You have to write it in the book, I’m not sure what the name is called that’s just what we call it.

You have to actively choose to use them by writing in the time in the punch communications log in your daily records book. Note that you are only supposed to use sick hours for medical appointments or missed shifts where you’ve called out. That being said, yes, that includes time when you’ve called out for mental health reasons. They are not allowed to ask for a doctor’s note or other proof that you were sick.

Edit to add: to be clear, I don’t know the exact policy on mental health days, but functionally, you can use them when you’ve called out because you’re not feeling well mentally.