ΔE 75.8, loose: different enough that you should pick on purpose. Frost is noticeably lighter, much more muted, cooler than Psychedelic Purple.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 76). Frost is noticeably lighter, much more muted, cooler than Psychedelic Purple.
The same difference applies the other way round: Psychedelic Purple is noticeably darker, much more saturated, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Psychedelic Purple on the colour wheel See Frost on the colour wheel
All matches: Psychedelic Purple equivalents · Frost equivalents