I do not think there is a specific disorder that your sister suffers from. She might have a severe personality disorder not otherwise specified (NOS) or she may just simply be engaging in maladaptive behaviors. It is difficult to know what causes her to behave in such a manner. Was she born that way as you believe or did something tragic happen to her that brought on such behavior? At the very least, her abusive behavior towards you was overlooked by your parents and because of this your parents may have inadvertently reinforced her behavior. They instructed you also to ignore your sister. This amounts to accepting her behavior, it came with no punishment.
Your parents seemed to know that something was amiss with your sister very early on but did little to stop her from behaving inappropriately. Unfortunately for you, you had to bear the brunt of your sister’s rage and anger and your parents probably did not know how to handle this situation. Perhaps if your parents had addressed your sister’s behavior with the assistance of trained mental health professionals early on, she could have been helped. It is difficult to know.
I am wondering about how your sister treats non-family members. Is she “normal” towards friends and co-workers and only abusive towards you and your mother?
As a child, her behavior “made more sense” and by this I mean it is not unusual for siblings to be jealous of the one another. But even as a younger child, she still took her disdain for you to extremes, and got away with it. As an adult, she still carries this disdain for you and now even treats your wife with disrespect.
Your sister has abused you physically, verbally and psychologically for years. You mentioned still seeing her for family occasions, and so forth and I am wondering why? Why spend time with your sister when she still abuses you? Why does she get to spend time with you or your family or have the luxury of being in your presence? My suggestion is that you do not spend another minute in her presence until she stops abusing you. Making rude comments about you and your wife is a form of abuse. Your wife will not allow this behavior and neither should you. Her behavior is simply unacceptable.
With regard to closure, realize that the probability of your sister ever changing is extremely low. Since you cannot change her, or force her into therapy, you will need to change your behavior and feelings toward her. She abused you your entire life and this should make you angry and not sad. It is sad that you will likely never have a good relationship with your sibling but that is the reality. It is her fault, not yours. It is time that you held your sister accountable for her behavior and this can start by you feeling a healthy anger towards her instead of feeling hurt by the fact that she treats you badly. I am not saying that you should act like your sister does and begin abusing her. I am just saying that you have the right to be angry at someone who continually abuses you. She treats you badly because she can and still there are no consequences. Do not allow her to abuse you any longer. Realize that she will likely never change and this realization may assist you in closure. I hope this answers your questions. Take care.
This article has been updated from the original version, which was originally published here on October 12, 2007.