Believability With Fictional Characters and Depression

My novel (WIP), Prisoners of The Mind, has been an ongoing project all year. I wrote it for NaNoWriMo 2013, and then completely started over at the beginning of this year with it. My NaNo draft of it had no plot and it was an unholy (no pun intended) mess. xD Of course, I'm not on the same draft I started with in January. There have been lots of "false starts" that I've set aside. I can't count how many uncompleted versions I've set aside!

One of my main reasons for having restarted so many times is that I struggle with making the characters' actions believable. My four FMCs are in an alternative mental health institution and suffering from some pretty serious stuff (Abby and Keri are both diagnosed as schizophrenics, yet not the same kind, but that's for another blog post). While I have family members and friends who've suffered (and some who continue to suffer) from various mental illnesses, I still struggle with whether or not I'm portraying these illnesses correctly. I've done research, but I still worry. I don't want to romanticize it or completely misrepresent it (like I've seen done way too many times with dissociative identity disorder).

I myself have struggled with depression. Not just "oh I've had a bad day" kind of depression. I mean full-out, I hate myself and am completely inadequate kind of depression. While I won't go into why I've had these feelings, it's never been an easy thing to deal with. At 14 I wanted to cut myself, and at times I still do. I can't remember what particular thought/feeling triggered that urge. I told my mother that night, and while I completely advocate having a support buddy (because a lot of times it's kept me from taking drastic measures), part of me somewhat regrets telling her it that night. Or rather telling her when I was having an urge. She (unintentionally) made me feel uncomfortable about the whole thing. To this day I don't tell her when I want to cut or am feeling inadequate, etc. I have an online buddy whom I'll talk to, and that has saved me a lot of times from taking drastic measures. I am forever grateful for that friend.

Keri Lanier, one of my FMCs, is diagnosed with schizophrenia before she enters the institution. But she also has depression. A lot of times I find myself venting my feelings (past and present) through her. She is a lot like me, both in personality and what she is suffering from. This is therapeutic for me in so many ways, and I think that maybe since I'm putting so much real life experience into her, that she will be believable. I hope she is. Maybe too with venting through her, I can let go of some of my own angst, and hopefully come to love myself more.

I'm hoping to have this draft finished by December 31st. If I can get better with character believability (I have a beta reader and then another person who edits my chapters. They both give me excellent feedback on my story.), hopefully I can keep moving forward and meet my goal of having a completed second draft by December 31st!