* Harley's trauma: The film hints at the Joker's abuse through Harley's mental state. She exhibits signs of Stockholm syndrome and appears to be deeply emotionally dependent on him.
* The Joker's control: The Joker is shown to be manipulative and controlling towards Harley. He uses emotional manipulation and gaslighting to keep her under his thumb.
* Past abuse: Harley herself mentions that the Joker "made her crazy," implying that he was the source of her mental instability.
* Violent tendencies: The Joker's history of violence and his overall personality suggest a pattern of abusive behavior.
While the film doesn't explicitly depict physical abuse, it heavily implies a history of emotional, psychological, and potentially physical abuse by the Joker towards Harley. This toxic dynamic is a key element in their relationship and fuels the narrative of the film.
It's crucial to remember that this relationship is portrayed as unhealthy and harmful. The Joker's actions towards Harley are not romanticized, and the film seeks to portray the dangers of abusive relationships.