Shock Treatment (1981)

In this offbeat melodrama, a crazed gardener is relegated to a mental hospital after he goes berserk and beheads his wealthy boss. The scuttlebutt in the courtroom is that the killer has stolen over a million dollars from his former employer and has hidden it on the estate. A professional actor is hired to feign insanity to get into the home, befriend the maniac, and find out where he hid the cash. Once he is admitted, the hapless actor encounters bedlam as he meets the patients, undergoes electroshock therapy, and suffers through several injections. Eventually he finds himself falling for a manic-depressive woman.~ Sandra Brennan, All Movie Guide