Drug-dependent (8)
I believe the answer is:
addicted
'drug-dependent' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for addicted that I've seen before include "Seriously devoted (to a particular activity)" , "Dependent on something habit-forming" , "Dependent on drugs" , "Dependent, hooked" , "Cadet did become compelled to use harmful substance (8)" .)