You can prefer Night Shyamalan's SPILT or THREE FACES OF EVE, starring Joanne Woodward in the split personnalities topics but this one is very good, and perfect for an ALFRED HITCHCOCK PRESENTS series episode. I am even surprised it has not been used in the old series, inspired by the Nunally Johnson's feature.
See also
Awards | FAQ | User Ratings | External Reviews | Metacritic Reviews