Institute providing support for fellow with a mental condition (5)
I believe the answer is:
mania
'mental condition' is the definition.
'mania' can be an answer for 'condition' (mania is a kind of condition). I am not sure about the 'mental' bit.
'institute providing support for fellow with a' is the wordplay.
'institute' becomes 'i' (common abbreviation as in MIT).
'providing support for' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'fellow with' becomes 'man' (I've seen this in other clues).
'i' after 'man' is 'mani'.
'mani'+'a'='MANIA'
Can you help me to learn more?
(Other definitions for mania that I've seen before include "Mental disorder that results in excessive or violent responses" , "wildness" , "Craze; overexcitement" , "Obsessive enthusiasm" , "Aberration" .)