How to detect a string that has repeated words?

Hi,
I have a list of title; however, some of them are repeated in a same cell
for example:
"Behind Blue Eyes"
"Better Man Better Man"
"You Know My Name You Know My Name"
"Word Up"

I want to detect the strings like "Better Man Better Man" and "You Know My Name You Know My Name"
Thank you!
(English is not my native language so i'm sorry if my writing is too hard to understand)

Assuming the text in your cells are not surrounded by quote marks...

=IF(LEFT(A2,LEN(A2)/2)=TRIM(RIGHT(A2,LEN(A2)/2)),"Double","")