Once Upon A Time In Hollywood followed Rick Dalton’s life closely, and while it didn’t explicitly mention a certain medical condition, it did leave some clues about it. Four years after his last film, The Hateful Eight, Quentin Tarantino returned with a new film that followed the steps of Inglourious Basterds by telling an alternate version of history. Titled Once Upon A Time In Hollywood, the story is set in the late 1960s and included many celebrities from the decade as well as Charles Manson (Damon Herriman) and his “family”.

Once Upon A Time In Hollywood introduced viewers to Rick Dalton (Leonardo DiCaprio) and his best friend and stuntman Cliff Booth (Brad Pitt), who had worked together for years and struggled to remain active and relevant in the final years of Hollywood’s golden age. The film also included Sharon Tate (Margot Robbie) and gave her a completely different ending, with Manson’s family members going after Rick and Cliff instead. Rick went from struggling actor to quite possibly having a second chance in his career following his near to death experience with the Manson clan, but underneath all the action and the ups and downs in his career and life in general, Rick was also dealing with his mental health.

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The film never mentioned Rick having any type of medical condition, though it did show him drinking heavily, to the point where it affected his performance on set. As it turns out, this was a coping method for him as he was dealing with a bigger problem, but he never knew – or at least not during the events of the film.

Rick Dalton Has Undiagnosed Bipolar Disorder

Rick Dalton stands by his pool with a flamethrower in Once Upon a Time in Hollywood

As mentioned above, Rick Dalton was a drinker, something that increased as his career got worse. One of the inspirations for the character was actor Pete Duel, who starred on the 1970s Western series Alias Smith and Jones and who died by suicide in 1971 after struggling with alcoholism and quite possibly an undiagnosed bipolar disorder. Speaking to Vanity Fair, Tarantino shared that DiCaprio needed more to find “his character” and so told him Duel’s story, which DiCaprio found useful when building his performance. Tarantino added that an undiagnosed bipolar disorder and not knowing how it works, with the “weird pendulum swings of emotion” that would bring, became something interesting that Rick could go through and was “solid ground” in which DiCaprio could work and build the character.

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Not explicitly mentioning that Rick Dalton is bipolar was part of the plan, as Tarantino wanted to show it through Rick’s actions. Throughout the film, Rick has various breakdowns of which many happen abruptly, such as the one in his trailer after forgetting his lines while filming the pilot episode of Lancer. His undiagnosed bipolar disorder would also be behind his drinking problem and how it got worse with time, as he used it as a coping method. Tarantino and the main cast of Once Upon A Time In Hollywood paid attention to even the smallest and most subtle details, and you might want to keep this one about Rick Dalton in mind the next time you watch the film.

Next: What Happened To Rick Dalton After Once Upon A Time In Hollywood