Experienced altered state with first of drugs (6)
I believe the answer is:
tasted
'experienced' is the definition.
(I've seen this before)
'altered state with first of drugs' is the wordplay.
'altered' indicates an anagram.
'with' is a charade indicator (letters next to each other).
'first of' indicates taking the first letters.
The initial letter of 'drugs' is 'd'.
'state' anagrammed gives 'taste'.
'taste'+'d'='TASTED'
(Other definitions for tasted that I've seen before include "Sampled (a food/drink)" , "Sampled (food)" , "Savoured" , "got a smack" , "Tested the flavour" .)