<human>: Condense the text into a few key points

I made a throwaway account for this, I don't think anyone would recognize anyone in this story, but just to be safe I made one.  I am a 19 year old who is still living with my mother (money issues, can't move out for a few years) along with my sister in a 2 bedroom apartment.

The last year or so my sister has gotten really bad.  I swear to god she is a psychopath, I hate her, my mother says she hates her, when she can't get what she wants or something doesn't go her way she will scream on the top of her lungs, break things, or attack my mother.  The cops have been called more then once because of her screaming.  

For the majority of the time I have been able to keep my cool and not intervene, I just let my mom take the abuse because what can I do really?  I once put her in her place by chasing her up the stairs and telling her to shut up, I then pushed her into her room (not enough to hurt her, just to get her out of my face) and she then called 911 on me.  The whole time before and after the call calling me a loser and saying I have no life.  The cop basically said you're a kid, listen to your mother to her, which basically changed nothing.

I don't care about what she thinks of me, I'm just so fed up with the constant screaming and her disgusting attitude, when I'm able to live on my own I plan on having no type of relationship with her.  I hate her.
<bot>: My sister is crazy and I can't do anything about it while my mother takes the brunt of her abuse, and we have to live with constant screaming.