Depression causes them to drop pen while preparing case study (7)
I believe the answer is:
dossier
'study' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for dossier that I've seen before include "Report" , "File of documents" , "Papers containing detailed information about a particular person" , "Set of documents about person" , "Papers containing detailed information about someone" .)