Hello... Thanks for sharing your situation... I hope to help you out in some way...
Here's my input on your current situation... THANK GOD, that you understand mental illness! Because if you didn't, I gurantee you'd have already left your friend behind... That is a major plus, and I can sense you may not say that NOW, but you will LATER... So hopefully everything goes ao'k...
One thing that I know you've got the ability to do, (As anyone with mental illnesses should/could/would do) is see things from another mentally-ill person's point of view... And that, simply put... Could very well save your friend's life... You've been thrust into a situation through which YOU can relate to, having been mentally ill... BUT, at the same time, no one wants to be in your current situation...
As it at times, seems that in similar situations to your own... YOU'RE, in charge of your friend's, "LIFE." And it is up to, "YOU," to save her life... HOWEVER... That is
NOT truth... If you're friend wants reacts badly to her psychotic symptoms, it'll happen... And there's
NOTHING you can do about it... And sadly... If she or anyone for that matter, decides to commit suicide, there's nothing no one can do to stop it... If someone wants to die badly enough, they'll get it done...
Now you've stated you've been through a bad depression... And any depression is bad enough to teach us all that our own life, lies in our own hands... So
PLEASE... Before doing anything about this situation... Just accept the situation that you've been thrust into, and accept that you are in it for a reason. And most
IMPORTANTLY... Accept that, "No matter what course of action you decide, or don't decide to take... You are NEVER in control..."
Now there are two sides to this... Any human can sense when another human is down, and could indeed commit suicide... Or do other forms of negative... If it comes to it... And if you have a gut feeling that your friend is going to do something terrible, and you're the only thing in between your friend, and what she's going to attempt... Then you have to do what
YOU think is right... But, as a human, and having gone through depression yourself... Accept any outcome... Because rightfully so, you are not in control of her life...
You need to accept this before you do anything... PERSONALLY, after reading all that you've written... I'd have to say that she definitely
NEEDS help... Now... You know that you wouldn't want your best friend telling anyone about your depression and personal problems... But if indeed, this is getting out of hand... There is nothing wrong with letting someone know about the situation... And I don't mean the internet... I mean someone close to where you are, someone who's capable of understanding quite literally: life, and death... And who's willing to go out of ones way to save a life...
Even if it costs a friendship...
One thing that I personally, as a mentally-ill victim, can admit... Is that in the beginning, it seemed as if everyone was against me... That everyone... Wanted me to fail, to screw up and do terrible things... But really... Everyone wanted the opposite... If all those people throughout my life, handn't have intervened when things looked shady to them, yet seemed completely perfect to me... I would not be where I am today... I would not have become who I am today, and I would have continued a long, lonely, negative, blind-path to nowhere... And if I only... Accepted... That we all have our own individual problems earlier on... Life might have seemed less serious... And more easily capable of becoming whatever it is we seek...
Now, in your current situation, you've stated that your friend only confides in you... I have to say... Right off the bat, that if anyone with schizophrenia says they confide in you, and only in you... They are most likely telling the truth... And that is a very hard thing to come by... So pat yourself on the back, because obviously you've got something rare.
If your friend indeed confides in you, you're off to a
GREAT start... Now, first off. I'd say in your current situation, asking your friend to go for help is the right thing to do... If that doesn't work, don't waste your time trying to force it... Because you've still got your friend's trust... Thats important... And thats more valuable to your friend, than it is to you... So
PLEASE, don't tick her off...
The next thing to do would be to go and fill in someone on the current situation...
BUT, make sure you don't act like you're hiding things from your friend... Schizophrenics are
VERY good at percieving attacks against them... They read into the slightest of things, and create big schemes in their mind... Which can sometimes come to be true... The reason I'm saying this, is because during the time that your friend doesn't accept help... Is the time that you should be looking for help... Provided you keep in mind that its her life, not yours, and you can't control, nor change her life; no matter what you do... Things just have to fall into place, and thats often not always caused by the forcation of being admitted to hospitals, or forced on meds...
I think one avenue that you
COULD try... And I mean, this is a
VERY delicate situation... So please, be sure YOU want to try this... If there is someone good to talk to... A councillor... A friend... Anyone but You... (Don't mean that negatively

) Someone around your school, that your friend knows you talk to... Maybe you could say that you would like her to come with you to see this person. Because if you can somehow, get your friend to start talking to someone else, aside from you... More people knowing about it, is better than less... If indeed, her life is on the line and help is needed... Which it most certainly sounds to be...
One thing that you said, is that you think your friend needs someone... Someone more, (Professional)... Now, from your standpoint, and hearing things from your point of view. I'd agree at first... HOWEVER... Maybe thats exactly what she DOESN'T need... I mean, she doesn't want meds... She doesn't want help... She needs a friend... And to be quite honest, some people who are schizophrenic, get better because they feel loved, accepted, and feel like they are being accepted for who they are... And maybe, your friend, feels that she can be herself around You, and ONLY YOU... Without the needs of medications... Councilling... Etc... And that could be the reason why she hides things from her family, basically everyone but yourself... And thats a GOOD thing...
ALSO... Sometimes... A friend, can't accept the embarrassment of asking some of the hardest questions in life... Therefore, they don't ask... It could be possible, that your friend is telling you, and only you, because she WANTS you to help her... I'm not saying this to confuse you, and I'm sure thats exactly what its doing... But I assure you, this is possible... I don't mean, that she's subliminally trying to tell you to call 911... I just mean... When someone is in a depressed, lonely, foreign, unpredictable state of mind... They give you a look... And this look we all know, for we all us it at some point in our lives...
Now lets say things were to escalate, and she got completely out of control... Have someone else standing by to help out... But make sure, like I said already, that the person you fill in, will not tell anyone else... And understands the seriousness of the situation... And understands the concept of life and death... And if you know, that you have to do something, and there is no waiting... Then call 911... There is nothing wrong with helping a friend, but its hard to help a friend who doesn't want, nor try to seek help for herself/himself...
Anything that happens in the future, just know that you're trying to do whats right... And if it costs a friendship to save a life... Let it be... And know that you did everything you could do, provided you're not in control... To save a life... Its a heart warming sensation when you save a life... I'm sure you know what it feels like... Do not be afraid, or feel like you need to escape your friend's problems... She's more afraid of you than you are of her... And maybe thats just whats keeping you and her from seperating... And understanding... A certain... Look in the eyes... Something that neither of you have to say in words, yet competely understand...
Don't forget, like what roses4lace said, you are not a counselor, your not a professional... Your task is to take care of yourself... this is true... Do what you think is right, and if you have to go further than your comfortable to go... Don't overstress yourself... Its now your problem... Its your friend... And any friend can agree, you need breaks from eachother.
Hope this helps... Whatever you decide to do, do it with the right intentions, and you can't go wrong...
Thanks,