Movies with imaginary friends?

Christine (Verina Greenlaw), about eight, a no-nonsense little Brit, and her invisible friend, Gretchen (age indeterminate!)

In the val lewton. ONe time.

A young woman finds her already unstable life rocked by the presence of a rambunctious imaginary friend from childhood.

The scene where Polly tapes up the jack in the box containing Fred was based off an actual incident that happened to a friend of co-writer/executive producer Carlos Davis named Steve Burnette. Burnette's mother Gloria had an imaginary friend when she was a little girl. But the girl's mother couldn't stand the fact that her daughter had an imaginary friend. It finally got to the point to where the Gloria's mother took her imaginary friend and flushed it down the toilet. This incident traumatized her for three years.

The film was unpopular with critics and Gene Siskel called the film "The worst film of 1991".