“Folie à Deux” does neither. Taking a cue from the last scene of “Joker” — a psych evaluation where Arthur hears Frank Sinatra’s “That’s Life” in his head and starts to sing along — the film is basically one long drawn-out courtroom drama, interrupted by musical numbers (old standards, most of them sung in Arthur’s head).

Instead of stigmatizing mental illness, "Joker: Folie à Deux" becomes a meditation on what mental illnesses can reveal about our societies.

Lady Gaga was the rare singer-turned-actress to launch a movie career to almost universal acclaim and awards attention. Has the “Joker” sequel misfire ruined all of that?