Mank director David Fincher has described Todd Phillips’ Oscar-winning Joker as “a betrayal” of mentally ill people.

In an interview with the Daily Telegraph, Fincher was reflecting on Joker’s surprise success at the box office in a wide-ranging attack on the risk-averse production strategy of the major Hollywood studios. Saying that studios “don’t want to make anything that can’t make them a billion dollars”, he also suggested that occasionally “challenging” material can get support, if there is solid previous evidence of commercial potential.

Without the example of The Dark Knight – a similarly dark-themed take on a superhero story – Fincher suggested that Joker, with its evident allusions to classic Martin Scorsese movies from the 1970s and 80s, would have struggled to get off the ground. Fincher said: “I don’t think ­anyone would have looked at that material and thought, ‘Yeah, let’s take [Taxi Driver’s] Travis Bickle and [The King of Comedy’s] Rupert Pupkin and conflate them, then trap him in a betrayal of the mentally ill, and trot it out for a billion dollars.’”

Joker, which won a best actor Oscar for its lead, Joaquin Phoenix, was criticised on its release for “perpetuating damaging stereotypes” in its characterisation of its central figure, Arthur Fleck, as a psychiatric patient who becomes violent after stopping his medication. In the Guardian, medical professionals Annabel Driscoll and Mina Husain described this as “not only misinformed but [it] further amplifies stigma and fear”.

In contrast, however, film-maker and disability activist Justin Edgar praised Joker as “a classic of disability cinema, a film that takes the experience of the outsider and makes us root for them”.