A patient does little to gain from this treatment (4-4)

I believe the answer is:

rest-cure

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'a patient does little to gain from this treatment' is the definition.
'rest-cure' can be an answer for 'treatment' (rest-cure is a kind of treatment). I am not sure about the rest of the definition.

'from this treatment' is the wordplay.
'from' becomes 'rest' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'this treatment' becomes 'cure' (medical treatment).
'rest'+'cure'='REST-CURE'

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I've seen this clue in The Globe and Mail.

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