You would have to do some searching for journal articles about case studies for answers to this. Is this for an assignment? If so, I suggest you go to your school or college library and ask the reference librarian for help in searching the right databases. Or you could search a public library’s social science and general scholarly databases for relevant articles. Hope this helps.

There is a fruit basket full of possibilities.
Consulting a professional is the only way to get a true scope.

Separation anxiety.
Watch the documentary Three Identical Strangers. Really good.