Treatment time dismissed by retired person trying to get clean (5)
I believe the answer is:
rehab
'treatment' is the definition.
(eg treatment for a drug addict)
I can't explain the rest of the clue.
(Other definitions for rehab that I've seen before include "help with addiction" , "Treatment centre (abbrev.)" , "Training and therapy after drug abuse" , "convalescent home?" , "Restorative care" .)