Has anyone ever heard of a 17 year old girl suffering from “Separation Anxiety Disorder”?

I know this is very common in toddlers who get upset and anxious when a parent has to leave them,but I’ve never heard of it in teenager? I’ve looked it up on the web and all the info I’ve found relates to babies. My partners daughter is 17 (she lives with her mother as her parents are divorced) gets anxious when she’s away from her mum. She’s OK going to college etc, but she can’t do sleep overs at friends houses and she has never been on holiday without her mother. According to my partner she has been like this since she was a baby and the mother encouraged it it seems as they had major problems with her being separated from her mother when she was a toddler and the mother wouldn’t let anyone hold her when she was tiny?

My daughter currently has it and shes 13. As you said it appears to be something that toddlers get but teenagers can get it too.
My daughter has always slept in her own bed in her own room, however due to lack of family support she has rarely spent a night away from us.
Now she wont do sleep overs, wont go on overnight school trips, hell I’m even struggling to get her into school in the daytime! The school are being fantastic and allowing her to half days so we can build her up. She was always the same in Primary school but they just put her in a corner and left her there, I never found this out until some months ago.
If shes away from me or knows shes going to be away from me its a total nightmare. I’m waiting for her to see a local mental health specialist because I dont know what else to do.
And the first person that says “take things away from her” or “offer her treats if she does well” will get a slap upside the head!! We’ve tried all that. From unplugging her tv, to saying she can have a hamster and guitar lessons if she goes to school with no problems. None of it works.
These kids need help that sadly us normal parents can’t give them.