Addiction treatment (5)
I believe the answer is:
rehab
'addiction treatment' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for rehab that I've seen before include "Course of treatment for addicts" , "Restorative care" , "Process of restoring, eg, an addict to health" , "convalescent home?" , "Treatment centre (abbrev.)" .)