About My Possibly Ill Teen Sister...

[shyuser]

Hi,
I recently stumbled across this forum and hope it can help me solve a question regarding mental health.
My younger sister is currently 18 years old, and she is entering her last year of high school. I'm worried because she acts very immature for her age and believes that she is better than everyone else. It surprised me that she even admitted it to our mom: she claims that she hates her friends, hates everyone around her, and calls herself a "queen". She is also very sensitive and cannot take critisism at all, even if it's plain old advice—she explodes and fights with anyone who says anything about her, and she does it in a violent manner involving hitting and screaming. She also tends to talk about herself and her problems all the time, and pretends she doesn't when we (me and mom) point it out. One other thing I've noticed about her is the way she can easily insult someone, even if they've completed a task for her. For instance, about two weeks ago I let her borrow $80 and told her that she needs to pay me back whenever she can. Not only does she refuse to pay me back, but she even called me a "fat, greedy b****" when i mentioned it to her.
Being 22 years old, this kind of behavior is past me. I don't react or find it insulting, but i am very concerned  for the people around her. I wonder if it's a mental disorder? Neither me, my mother, nor my two older sisters ever behaved this way at 18. I also wonder if my younger sister is perhaps mentally developing late? She's always stuck in the past as well and blames everything (including her outbursts) on our mother. I think it's narcissistic personality disorder? Correct me if I'm wrong! Thanks for your help!

[Ps_Kel]

As a Youth Worker and having 2 older sisters when I read this it sounds completely normal for the youngest child. Their whole life they have gotten what they have wanted .. they are the 'baby', every one tends to their needs. (this was actually me!)
not nacissitic, but merely immature and niave. adolescence is now seen to extend all the way through to 25 (maybe even 30!) and for the youngest in a family, it means they remain a child longer and only will mature later in life. this will mean that the world revolves around them more than normal - haha.
she is fine.
and will be fine.
sorry if the outbursts happen on you - youre her sister.

[RockRose]

It does sound like narcissistic personality disorder.    Recently,  there is a theory that NPD begins in early childhood when a child is continuously given the message that they aren't adequate,  and don't measure up to standards in the family.    I do see that as a possible dynamic in your family - when you say that neither you,  your sisters or your mother had behaved like this.  That's a small thing,  a small detail in your writing,  but it seems to paint a picture of pointing out that she's not like everyone else in the family.  In descriptions of people suffering with mental illness or a personality disorder,  I'm not sure it's necessary - or typical - to state that the person isn't like all the rest of the family.  

I'm not sure if this kind of upbringing is true of all narcissists - I think there are many who had perfectly supportive families - but it bears a read.

https://www.psychologytoday.com/blog/evolution-the-self/201110/the-narcissists-dilemma-they-can-dish-it-out

[AnnieBrooke]

Maybe.  But really as her sister (not her mother), and I say this from the heart and with respect, as an older sister of three sisters, it is not your role to be diagnosing her.  One thing youngest sisters ALWAYS explode at is being patronized by their older siblings, even if they are emotionally normal.  

If your mom does not know what to do, she should talk to a doctor.  You should write off the $80 as a lesson learned, have her sign an IOU any time in the future that you loan her money, and FORGET IT.  Forget that she exploded and called you a name, just forget it all.  Life is too short to say "I did this and she did that and I did this and she called me a NAME!!!"   Keep out of the business of giving her "plain old advice."  The youngest girl of 4 is going to hate hate hate getting "advice" from a sister.   It feels so overbearing as to make even the mildest person explode.

Tell your mom that she should make an appointment with a mental-health counselor to discuss your sister, and then BUTT OUT.  Don't go along, don't coach, get out of it.   Resist the urge to act superior to your poor troubled little sister when you discuss her.  Support her by acting like you think she is fine and can do it, or just stay away.  Live your own life.