Past drug offence raised worry (7)
I believe the answer is:
agonise
'worry' is the definition.
(to agonise is to worry or fret)
'past drug offence raised' is the wordplay.
'past' becomes 'ago' (similar in meaning).
'drug' becomes 'e' (E is another name for ecstasy).
'offence' becomes 'sin' (a sin is an offence or transgression).
'raised' is a reversal indicator (going up in a down clue).
'e'+'sin'='esin'
'esin' written backwards gives 'nise'.
'ago'+'nise'='AGONISE'
(Other definitions for agonise that I've seen before include "Struggle mentally" , "Worry greatly (over something); I go sane (anag.)" , "Suffer torment" , "Suffer extreme mental pain" , "Labour" .)