On the back window of a car was a sticker saying
Ummm … is she a physical bitch, a psychotic bitch or both? Sitting in a different car, I didn’t get the chance to ask.
It is very easy to get the phys– words and the psych– words mixed up, and to mis-spell them even when you’ve got the right one (especially if you’re writing in ALL CAPS). The phys– words come from Greek φυσική physike (nature) and Latin physica (study of nature) and the psych– words from Greek ψυχή psyche (breath, soul) (note that ph, ps and ch are all one letter in Greek).
In any not-completely-informal use, physcho is wrong, but some people use it, whether deliberately or accidentally (definitely accident with reference to Alfred Hitchcock (who is more associated with the word than Robert Bloch is)). Did the sticker company use it deliberately, thinking either that the people buying it wouldn’t notice, or would notice but wouldn’t care, or accidentally, realising later (in which case the two previous questions again) or not?