In a 2018 UK Guardian interview, Nicolas Cage described his performance's inspiration: only just before shooting started, his 14 year marriage to Alice Kim Cage came to 'a sudden end', which was "A shocker for me... didn't see it coming, and those feelings had to go somewhere, so they went into my performance."
Actor Richard Brake (who plays The Chemist) revealed on Twitter in Dec 2018 that in an early draft of the script the caged Bengal Tiger "Lizzie" was a lizard. Brake recounted that when he arrived on set director Panos Cosmatos said "Oh, by the way: Lizzie's a tiger now."
According to co-writer Aaron Stewart-Ahn, when he and Panos Cosmatos presented Mandy (2018) at the Cannes Film Festival, Cosmatos described it as a film about the death of his parents.
There are several similarities between Jeremiah Sand and real-life cult leader Charles Manson. Like Sand, Manson was a failed musician who reportedly took it very personally when his musicianship was insulted. Sand refers to his victims as "pigs," as did Manson and his followers. Psychedelic drugs were also used before acts of violence.