Suffering narcolepsy, go for help with diagnosis (12)

I believe the answer is:

laryngoscope

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'help with diagnosis' is the definition.
I can't tell whether this defines the answer.

'suffering narcolepsy go' is the wordplay.
'suffering' is an anagram indicator.
'narcolepsy'+'go'='narcolepsygo'
'narcolepsygo' with letters rearranged gives 'LARYNGOSCOPE'.

'for' is the link.

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I've seen this clue in The Times.

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