I really like this movie a lot, but the first two times I watched it, the damn thing felt like it was 4 hours long. Each time!!! In truth, it is only an hour or so long. At least, the version most people see is only that long. There is a longer version of it, if I'm not mistaken.
Actually, it runs to about 58 minutes or there about. Though that might be the slightly longer version, which is known under the title Dementia, which had to be cut slightly in 4 places to get past the New York City film censors.
Though, neither film is to be confused with the Filipino horror film Dementia from 2014 or Dementia 13 from 1963, which was Francis Ford Coppola's 1st legitimate mainstream directorial effort.