I agree with lindahand. All of the friends from my past who did nothing, I am angry at them to the deepest level now, because they observed me falling into such a horrible place and stood by and watched. No one even tried to bring it to my attention. I feel completely betrayed. I had already stopped being friends with all those people for other reasons, but I look back and I say "why? why? why? why didn't anyone even try??"
If there was one person who even tried, I know today they would hold a special place in my heart. Even if I had been angry at them at that time, today I would see that they actually cared about me and were a real friend, instead of the fake friends that I had back then.
She may get really pissed off at you for a while, but it is time to tell someone. Those symptoms are quite often treatable with the right medications. It takes time but she can most likely be helped. It would be rare if she wasn't helped at least somewhat by the medication.
I remember telling a parent that a friend had just taken a bottle of tylenol (which is actually a fairly lethal thing to do - slow horrible death - but I digress). Had I not said anything she'd be dead or have liver failure by now. Oh boy was she ever pissed off at me. She didn't want to speak to me for ages. Now we are both adults she credits me with saving her life and we are good friends.
Your friend is in a very scary place right now and needs help to get out of it. In the overall scheme of the world it is worth losing her as a friend for a while so she can get the help she needs. My guess is once she is stable you'll be even closer friends. But likely not right away.
Sounds like it could maybe be both a mood disorder and a schizo related disorder but negative symptoms of schizoaffective disorder or schizophrenia are hard to tell apart from depression and only a psychiatrist would be able to do such a thing. My psychiatrist told me straight off the bat when I started mentioning some negative symptoms I have that negative symptoms and depression often overlap with each other. I would less worry about figuring out what it is on my own and more worry about helping her get help as some of that stuff in concerning.
Well, not being a doctor, the things you describe are concerning. It does sound like something is wrong. It would be a good idea for her to talk to an adult about her problems and see a psychiatrist. Let her know you are concerned and want to help her because you're her friend. If she has a good relationship with her parents have her talk to them first. If she's afraid, maybe say you can be there for support. It is a hard thing to ask for help when things are not going well. Sometimes you don't realize how bad things are or are in denial about it. But if she is worried about her thoughts that is a good first step.
She should see a doctor right away, a psychiatrist would be best. She may need to see her primary physician first to get a referral. If she has a bad relationship with her parents perhaps a teacher or school administrator can help.
It is good you are worried about her, you're a good friend. Hopefully she can reach out to an adult and get the help she needs.