From an adult in the U.S.: I have a question regarding my younger half sister’s odd behavior. I’m curious to know if she has Cinderella Persecution Syndrome or Narcissistic Personality Disorder, or possibly both.
She was very spoiled and babied as a child due to having ADHD and learning problems, and seems to have developed a swelled head due to the spoiling. She acts like she’s better than those around her, and has openly admitted she thinks she is better than me and our two siblings (she got drunk once and said “they aren’t worth shit compared to me”) and frequently gets all nose-out-of-joint over any attention our parents pay to me.
Growing up, she treated me more like I was the hired help in our home ordered me around, and told friends of hers that I wasn’t really her sister, when we have the exact same mother (we just have different fathers). But at the same time, she acts like some poor hard-done-by Cinderella who’s being “picked on” by me or other people in the family, when we aren’t picking on her: she’s just misinterpreting our words or actions. For example, she believes that I think she’s stupid, when I don’t think any such thing about her.
She even thinks her kids are being picked on: I can’t even answer her kids’ questions without her flipping out at me and treating me like I’m picking on her kids and putting down their intelligence, which I’m not. I’m just answering their questions, nothing more. So, what do you make of this? Does she have Cinderella Persecution Disorder or Narcissistic Personality Disorder, or both? And what can I do to better get along with her?
Does the name of a diagnosis matter? She is a difficult person. You’ve done your best to stay in relationship with her despite her terrible behavior. At her age, she is unlikely to change unless she somehow realizes how sad it is that she is missing out on having a positive mutually supportive sibling relationship.
I can’t make a diagnosis, but I can confirm that she is a troubled person. I can also sympathize with you about how difficult it must be to put up with her.
To answer your question about how to get along better with her: You may not be able to do any better than you are already doing. The key is not to expect anything from her. You know who she is. It’s unlikely that there will be any new information. All you can do is be reasonable yourself and not let her behavior get to you. If you are having trouble doing that, it might be helpful to see a counselor to get some practical advice.
I wish you well.