I was diagnosed with Massive Depressive Disorder almost 20 years ago, and due to incredible doctors and meds, my illness doesn't really impact me anymore. In fact, I'm an advocate for "endthestigma" and have worked hard to show that mental illness, when controlled, is no different than diabetes, hypertension, etc.
When I get to the question on job apps, I've been putting checking "rather not say". I'm wondering what everyone else is doing. When you answer, you certainly don't need to say your illness.