My spouse’s 16 year old daughter is mentally ill and in treatment.
(She has been diagnosed with Reactive attachment disorder (RAD) and is
This sounds like a difficult situation. It's hard to give specific advice in such a complex situation, but I'll try to give you some ideas that may help.
Of late, her behavior has worsened to the point where
she responds with screaming to most if not all requests (such as
cleaning room or to pick up after herself). She is particularly
aggressive with me.
It seems like you sometimes try to (help to) discipline her. While not necessarily a bad idea, discipline and setting boundaries is:
- always a difficult part of parenting
- particularly difficult for a step-parent
- even more difficult if the relationship is like you describe
So my first question would be: Is it really worth the fight to try this? To put it bluntly: If nothing comes of you trying to make her pick up after herself, consider dropping the attempts. Yes, I know this sounds like "giving up", but you tried, it did not work, and maybe it's time to try a different approach.
Instead, speak to her parent (father?), explain that it makes you unhappy / annoys you if she e.g. does not pick up things, and try to find a solution. Maybe her parent needs to speak to her, maybe the three of you together... . The parent is a) responsible for the daugher, and b) invited you in their life, so they have a certain responsibility to both of you, and thus needs to be involved in finding a solution.
Since I 1) see her for about 20 min a day to an hr [due to nature of
my work schedule] 2) am never communicated with by her therapist [the
family of the former step-parent pay for the treatment] 3) was never
integrated into her life when I came into it 2 yrs ago—what, if
anything, can I do and how much if it all should I be involved?
Again, that's not something we can answer for you. How much you want to be involved is something all three of you must decide (independently, then together). You will have to find a balance: On the one hand, you (presumably) live together, so you will need to find some common ground. On the other hand, the daughter is not your daughter, and almost grown up, so you can't expect her to want to cuddle you every day...
Again, try talking to the parent and her (you may sense a déjà-vu here ;-) ).
Finally, my personal advice would be for you to try and find a counselor for you. This is a very tricky situation, and I believe you could use someone help you navigate it. You could go with your partner, maybe even (later) all three, but consider going alone first, just to get your own things sorted. Talking to a trusted, good friend or relative is also an option, but IMHO a professional, who is not involved otherwise, is often even more helpful.
Personally, I have encountered difficult situations, and a few hours of counseling have greatly helped me. Best of luck to you!