She leaves behind three kids: her adopted son Kevin Pearce, Lord of the Rings star Sean Astin, and actor Mackenzie Astin. "She will be greatly missed". "And I've loved watching people's reactions and talking about it and stuff".
Patty - who underwent a heart bypass in 2004 - shot to fame as a child when she played the role of Helen Keller in "The Miracle Worker", for which she scooped an Oscar, in 1963.
He said he has been touched by all the support from his extended family, something not everyone knew was so important to her.
She returned to social media on 15 March to mark her 30th wedding anniversary, writing, "30 years ago today, Mike and I married". By 8 years old she was largely under the control of husband-and-wife talent managers who kept her busy on soap operas and advertising displays.In the meantime, they supplied her with alcohol and prescription drugs, which accentuated the effects of her undiagnosed bipolar disorder.In her 1988 memoir, "Call Me Anna", Duke wrote of her condition and the diagnosis she had gotten only six years earlier, and of the subsequent treatment that helped stabilize her life.
"It got hard for her to travel", Astin said.
Sean mourned the loss of his mother Tuesday afternoon on his public Facebook page, which posted a photo of a baby - likely Sean himself - in his mother's arms.
"This morning, our beloved wife, mother, grandmother, matriarch and the exquisite artist, humanitarian, and champion for mental health, Anna PATTY DUKE Pearce, closed her eyes, quieted her pain and ascended to a attractive place", Astin wrote.
But it's Duke's advocacy for mental health, in particular, that resonated with fans in deeply personal ways.
"I choose to take responsibility for those things that I did, and I tried to not - you can't fix them", she added. "She's free. She's free". "We celebrate the infinite love and compassion she shared through her work and throughout her life". "It's thrilling for me to say 10 years of a healthy life".
Patty took the role to the big screen in 1962, and won a Best Supporting Actress Academy Award for her portrayal.
Patty Duke was 16 when she won the Academy Award for best supporting actress for her work in "The Miracle Worker".
But producer Sidney Sheldon had noticed that she had two distinct sides to her personality and the two came up with the idea of a show about "identical cousins" with contrasting personalities, and even different accents. Patty played herself from her 30s onward.
She went on to a have a successful television career, starring on "The Patty Duke Show", whose three-season run churned out more than 100 episodes. She was also married to actor John Astin.
Michael Pearce was the actress' fourth husband.