I don’t understand your question! If the person your dating would care WHY would you keep iit a secret? Just to make further trouble? And If they would not care, WHY would you mind letting them know?
Most people would care, and would likely not agree to even go out if they knew. (Not that anyone is at fault for a mental health issue, but that’s human nature.) The idea of waiting to tell is that the other person might agree to overlook an issue once they have gotten to know the person. Yet, it would be unfair tho let it go too far without disclosing an issue.