Did cast play junkies? (7)
I believe the answer is:
addicts
'junkies?' is the definition.
(junky is a kind of addict)
'did cast play' is the wordplay.
'play' indicates an anagram.
'did'+'cast'='didcast'
'didcast' is an anagram of 'ADDICTS'.
(Other definitions for addicts that I've seen before include "People who are hooked" , "Habitual drug users" , "Junkies" , "People with compulsive ailments as for drugs" .)