Released in October 2019, Joker is a psychological thriller detailing the disturbing transformation of anti-hero Arthur Fleck into the titular DC Comic supervillain. The film has garnered huge commercial and critical success, in particular an Oscar for best actor for the title role. Yet, to quote from a rival superhero movie, with great power comes great responsibility. Arthur's struggle with mental illness is a key theme in Joker, and its portrayal could have a powerful effect on public attitudes towards real people with mental illness.

Joker initially shows the public some of the problems faced by those with mental illness. Notably, effects of underfunding are underlined when Arthur stops receiving regular treatment, despite evident willingness to go to therapy and take medication. The impact of past abuse and family modelling of mental illness are highlighted as factors influencing Arthur's behaviour. Overriding metaphors such as Gotham's bleak cityscape and Arthur's dismal apartment mirror and reinforce the difficulties the character faces, leaving the viewer sympathising with his plight.

Joker portrays multiple episodes of brutal violence. In the opening scene Arthur is assaulted by a group of youths, accurately reflecting the fact that the mentally ill are at increased risk of being victims of violence. However, as the film progresses, starting with self-defence, Arthur turns to violence himself, and does so with increasing frequency. Crucially, this violence is causally linked to his mental illness. First, violence increases after Arthur stops his medication. He makes a ‘joke’ (‘What do you get when you cross a mentally ill loner with a society that abandons him and treats him like trash? I'll tell you what you get. You get what you f***ing deserve’) that explicitly references his illness as a cause of his subsequent murderous act. In the final scene, Arthur is seen in a psychiatric hospital, leaving the viewer with the conclusion that his mental illness was the cause of his crimes, for which he was admitted to hospital rather than imprisoned.

As healthcare professionals, we can see the mental illness and violence as two separate parts to Arthur's character, albeit with common risk factors. His violence is primarily for revenge and is often conducted in a calculated, organised way. It is not linked to delusions or hallucinations. His attention to his appearance and his degree of planning increase as his violence gets worse, the opposite of what would happen in deterioration of mental illness. Nonetheless, we believe that the conflation of mental illness and violence in this film is likely to give the public the impression that people who are mentally ill are likely to be violent, reinforcing the stigma of a fairly common stereotype.

The film's ultimate motive is entertainment, not education. And although Joaquin Phoenix's performance is indeed powerful, in a climate where the US President has made remarks such as ‘mental illness pulls the trigger, not the gun’, there is the danger that the film has increased the stigma towards a group who need support, not fear (or worse) from their community.