I'm afraid: she may be bipolar

Her mother is bipolar.
She tells me how she'll randomly break out in tears more than usual.
She seems to have insomnia, sleeping only 2 hours a night.
With bipolar symptoms, do they start of discreetly then grow over time, she's 17.
If not then I think she has depression... but it's not like i can just walk up to her and say "You need proffessional help"... Plus I think she's seen therapist/psychologists before.
?

Thanks^^although its her mother that has bipolar- its just my friend gets put through so much, the bad days when her mum tells her that she should have never had been born, her stepfather-is an angry person and sometimes lashes out, her other friends treat her like shes invisible: I just wish something good would turn around in her life, she deserves it

I thought for the longest while that I was bipolar but my brother convinced me that I'm not and that I'm just depressed. Sometimes I still think I am and I want to get help but he talks me out of it.

I guess i'm a little confused...
what's so scary about being bi-polar?

^^ You're funny... a little bit rude...but funny

You seem like you have a good outlook on life.

That's good.

^^true true... im just worried for her sake, I don't think she could handle it. She's put through so much, I fear that this may be another crappy thing for her in her life (i have nothing against ppl who r bi-polar) -I'm just worried for her well-being and state of mind :(

Yeah, I would be worried about that to. But doesn't therapy fix that?