I was wondering about this as well so I was glad Frayling commented on it in his documentary.
Sir Frayling suggested it was kind of naive "Reefer Madness" take on marijuana.
However, he also claimed Indio was a true psychopath if not extremely disturbed.
I personally believe mixing the two doesn't make the scenes in question "naive"
Maybe melodramatic but not naive.
As already stated Indio gets a calming sensation and doesn't start believing he can fly.
