Jane Fonda‘s life has certainly seen its fair share of both trauma and triumph over the past 80 years.
Still, the actress and activist says one of the defining moments of her life was her mother’s suicide in 1950, which happened when Fonda was just 12 years old.
In the new HBO documentary, Jane Fonda in Five Acts (out Sept. 24), the star of Grace and Frankie opens up about growing up with a mother who was bipolar—and how she eventually learned to understand and forgive her.
“If you have a parent who is not capable of showing up, not capable of reflecting you back through eyes of love, it has a big impact on your sense of self,” she tells PEOPLE editor-in-chief Jess Cagle, in the latest installment of the Jess Cagle Exercise on PeopleTV.
“As a child, you always think it was your fault…because the child can’t blame the adult, because they depend on the adult for survival. It takes a long time to get over the guilt.”
Frances Ford Seymour, a Canadian-born socialite, was married to Henry Fonda in 1936 and they had two children: Jane and Peter. In 1950, when Jane was 12 and her mother was 42, she took her own life by slitting her throat while at a nearby mental institution.
Henry Fonda told Jane and her bother that their mother’s death had been a heart attack; Jane only found out the truth by reading about it in a movie magazine.
“When I wrote my memoir [2005’s My Life So Far], I dedicated it to my mother because I knew that if I did…I would be forced to really try to figure her out,” Fonda says. “I never knew her because she suffered from bipolarity.”
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Fonda was able to access her mother’s medical records, and not only learned that she’d suffered from the disorder, but she really dug into her background—as well as her father’s— to try and better understand who they were as people.
“When you go through that kind of research…if you can come to answers, which I was able to do, you end up being able to say, ‘It had nothing to do with me,'” Fonda says.
“It wasn’t that I wasn’t lovable. They had issues,” she adds. “And the minute you know that, you can feel tremendous empathy for them. And you can forgive.”