Ten years ago, Lee Daniels announced he was taking on a movie project based on the real-life case of Latoya Ammons, a single mother who claimed that her house was haunted, that her children were being possessed by evil spirits and that she needed a “deliverance” – in other words, an exorcism. Well, the resulting very silly and mediocre movie has now finally arrived, with Ammons in real life having long since moved out of the house in question; it has itself been bulldozed, and some of the more excitable and credulous media coverage which helped clinch the film deal has cooled in retrospect, leaving behind, perhaps, a greater emphasis on those heartless observers who were callous enough to wonder if Ammons’ paranormal claims were a drama-queen ruse for avoiding the rent and bamboozling social services.

Daniels could have made a brilliant, heartfelt film about the Ammons case, which absorbed precisely that possibility; the possibility that it wasn’t real, but real in another sense, a film that proposed “possession” as a metaphor for the racism, sexism, poverty and class prejudice that creates dysfunction and delusion in a family in this situation. And for a while, it looks as if Daniels is doing that, with robust and potent performances from Andra Day as the mother, Mo’Nique (so powerful in Daniels’s film Precious) as her social worker, and Glenn Close as Alberta, the cranky born-again Christian grandma, with Close giving this black-comic role both barrels, just as she did playing JD Vance’s crotchety Mamaw in Hillbilly Elegy.

The scares are also withheld for a good long time, and for a while The Deliverance looks like a social issue drama with a weird shiver of unrest, the kids being apparently unable or unwilling to explain to the social worker how they got their bruises. And when something horrible happens at the kids’ school, and psychological explanations are still viable, the movie actually packs a De Palma-style punch.

But then, with a terrible inevitability, it just turns into a big, standard-issue derivative sub-Exorcist slice of ridiculous nonsense in which, like so many real-life exorcism films (for example, The Conjuring 2, about the Enfield poltergeist case), nobody involved has apparently seen the film The Exorcist. Nobody in fact acknowledges the very great resemblance between that globally familiar fantasy and what they’re claiming is the truth. This film is covered in a thick ectoplasm of disappointment.

• The Deliverance is in US cinemas from 16 August, and on Netflix worldwide from 30 August.