I can only answer you based on my own bitter experience with this issue. Basically, every time I have told someone about my psychopathology, I have become used toilet paper.

DO NOT TELL NEW FRIENDS ABOUT BP. Period.

Here's why:
- Even if they're the nicest and most well-intentioned people on Earth, they almost certainly fear mental illness and all people affected by it. This is most likely because of ignorance. Why does a non need to know about mental illness ?
- Even if they don't abandon you completely, you will almost automatically get put in a different category in their minds. They will no longer treat you the same way. They may stay away more, talk less, hang out less. You may be excluded from parties, whatever. Again, ignorance !

The only time I would tell someone is if:
- I don't care whether or not they leave.
- I have known them a long enough time to have the trust that they will understand and accept me. I would have to be very sure (almost certain) about this.
- They need to know ... in the impossible event that I'm about to marry someone, she needs to know.

Also, I wanted to question what you said about "not being honest". I disagree ... health issues, esp sensitive ones like mental illness, are extremely intimate personal details that need not be told to ANYONE other than your doctors. Let's say your best friend has genital herpes. Do you think he/she will straight up volunteer that info ? Nope, he/she doesn't have to.

That's how I see it.