It depends. Usually, when there is enough trust built up and you sense that your partner will be understanding, this is a reasonably good time to have the conversation.
It would be best for that "someone" to hear it and be educated by the treating physician/psychiatrist.
I don't think there is a test to tell if someone is bipolar. I think doctors rely mostly on symptoms of the patient, and observations of the patient.
Ask herHowever, I would tread carefully here. Implying that someone is bipolar just because they are not interested in you is going to come across as judgemental and arrogant. Better to simply ask if they are interested in you, and leave out the biploar part.
stupid question
Just tell them that you need to talk to them, and that what you are about to tell them that they shouldn't get mad at you because you have your agency to do what you want and then tell them you were dating someone.
Don't do anything that would break them up, but it wouldn't hurt to tell them that you like him/her. Just keep in mind that they are dating someone, so don't expect them to ask you out or anything. You can always just be friends.
confront them
Tell them you are already taken.'nuff said
You need ton confront the person you were kissing (if you were in fact kissing them) & ask them if they are dating someone else; if they are, leave them alone. If they're not, tell them that someone (don't mention names) told you that they were dating someone & you just wanted to ask for reassurance.
if your boyfriend has bipolar and doesn't want help you still might need to tell someone close to him or a parent to help but you also need to talk it through with him also and see what needs to be done
You should just sit your mom down and talk to her the way you would about anything else if you need to tell her about dating someone who has a criminal record.
you should tell her how you feel and if she isn't understanding then she can't be that good of a friend