In real life, there are only 3 people who know I'm bipolar: my pdoc, my therapist, and my regular doc. That's it. I haven't even told my family because they're ignorant people when it comes to mental illnesses.

Who you choose to tell is completely up to you. You can still maintain your friendships, job, school life, etc. without having to tell anyone.

When I was in grad school, I think my lab professor suspected something was wrong with me, but she never said anything to me about it and I didn't say anything to her either. She kinda brushed it aside. Other people in my research lab accused me of having ADHD and other things. I just told them "I don't have it" and that was the end of it. (I think what they witnessed was hypo/mania.) So while it's true that you can't stop people from suspecting things, that doesn't mean you have to tell them anything.