Under the influence of drugs (4)
(Other definitions for high that I've seen before include "Shrill" , "Anticyclone; euphoric" , "Elevated; euphoric" , "Tall - loud - under the influence of drugs" , "(Of meat) slightly decomposed" .)
'under the influence of drugs' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for stoned that I've seen before include "On a drug-induced high" , "High on drugs or alcohol" , "with jewels" , "attacked with missiles" , "Executed in Biblical way, or slangily drunk" .)