Trouble and a brief time when you can't think clearly (5,4)

'you can't think clearly' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'trouble and a brief time' is the wordplay.
I cannot really understand how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is found in the answer.
'a' is found in the answer.
'time' could be 'ad' and 'ad' is found in the answer.
an anagram of 'brief' is 'brife' which is present in the left over letters.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).

'when' is the link.

Can you help me to learn more?