please help

i used to be good friends with this girl, but over time we started drifting apart. we basically have nothing in common anymore and we don't talk much. she doesn't seem to have much of a personality, but rather her personality changes to fit the personalities of other people she surrounds herself with.

she met a guy and was smitten with him within a week; they took their relationship very far in the span of one week, and soon after that, it was over.

ever since then, she has been more depressed than ever. i think she has always been depressed, but she has developed substance abuse problems. she claims to want help but has made no move to get help, she sneaks around everyone's backs, drinks often, etc. she seems to have complete disregard for anyone and she is behaving selfishly. she uses her problem as an excuse for her frequent bad behavior, and has become very manipulative.

she has admitted that she makes up things in her head; and knows they are untrue but she will believe them/spread therm around anyway.

i don't want to turn my back on what was once a good friend, but i don't know how long she will continue to hurt and manipulate everyone around her. she is 21. her parents seem aware of the issue but not completely. they seem to be trying to help her but...not trying their hardest.

i keep telling myself she has a problem. i don't want to be a bad friend. =( i've never known anyone in her situation, so i don't know what to expect or how to deal with it

Hi, cece5300! It does sound like your friend might have low self esteem and depression. All you can do is tell her that you will be there for her if she needs a friend. Getting help is her responsibility. Maybe you can try to find out if anything happened to her to make her behave this way.
Having this problem does not give her an excuse to treat people the way she does.