8 Little Known Nuances That Made Margot Robbie's Harley Quinn Awesome

8. She Researched Co-Dependent Relationships & Mental Illness

Robbie has stated in interviews that she struggled to get to grips with Harley's mindset while researching the character, saying, "I just didn’t understand how she could be such a badass and then fall to pieces over some guy. I found that really frustrating."

But things became much clearer when her acting coach recommended she read Sam Shepard's 1983 play Fool for Love, which revolves around an unhealthy co-dependent relationship. Robbie said of the play:

"Once I could view it in those terms, it suddenly made sense, and I suddenly had so much empathy for Harley and after that it was all very straightforward. It was fun after all that."

"I landed upon co-dependency as the tact to take. It's like a compulsion, I suppose. When you start looking at it the way an alcoholic is compelled, you know, needs to have a drink. You think of it in those terms, like it's an actual psychological problem, which co-dependency actually is."

Robbie didn't stop there, though, conducting additional research into co-dependence, even playing it out for real by keeping the live rat that Jared Leto sent her. "If Harley got something from Joker, she'd probably cherish it", she reasoned.

As for Harley's precise mental state, Robbie dug into the MMPI (Minnesota Multiphasic Personality Inventory) tests, working through hundreds of questions in-character to determine Harley's real-world pathology.

She also consulted a less-conventional resource for further help getting into Harley's mindset:

"I watched a couple of TED Talks about schizophrenia and that really helped because the women who were doing these talks were so intelligent and Harley needs to be wickedly intelligent, but also kind of psychotic."