The most common and most likely answer to this crossword clue is the 6 letter word MASHED
I've seen this crossword clue in Financial Times
M
A
S
H
E
D
More clues leading to the result MASHED
Buddy explains!

The straight part
We know that "Stoned" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case stoned = mashed.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MASHED mean?
MASHED verb- To convert into a mash; to reduce to a soft pulpy state by beating or pressure
- In brewing, to convert (for example malt, or malt and meal) into the mash which makes wort.
- To press down hard (on).
- To press.
- To prepare a cup of tea in a teapot; to brew (tea).
- To act violently.
- To flirt, to make eyes, to make romantic advances
- Broken up into a pulpy state.
- Intoxicated