The Simpsons season 27 episode 8
Episode title: Paths of Glory
Lisa sets out to restore the tarnished reputation of Springfield’s first female inventor. To find her invention, she scours an abandoned asylum and a restaurant that caters to men. Bart joins Lisa at the asylum, stealing one of the homicidal patient’s notebooks, and bragging to the boys at school that he wrote the entries himself. This revelation causes Homer and Marge to believe he is a sociopath, which Bart decides to use to his advantage until things go too far.