Marcia Gay Harden on "The Seasons of My Mother": "I didn't want her legacy to be Alzheimer's"

Academy Award-winning actress Marcia Gay Harden is sharing her mother's struggle with Alzheimer's in her new book, "The Seasons of My Mother: A Memoir of Love, Family, and Flowers."

Harden told "CBS This Morning" she was propelled to write the book to turn her own pain into something positive and to preserve the memory of her mother's life before she suffered from the disease.

"I didn't want her legacy to be Alzheimer's. I wanted her legacy to be this beautiful life that she's lived and that's really why I wrote it," Harden said. "There's no bright side to Alzheimer's, although there is a hope around the corner for drugs, but in the moment there's no bright side. And so you can only repurpose your pain toward something positive."

Harden also saw the book as an opportunity to reflect on the lessons she learned from her mother.

"There was one passage in it where I talk about my mother's, what I assumed was my mother's, passivity. My mother said if you can't say something nice, don't say anything at all. So I thought that was passivity and as I got older I realized that wasn't passivity, Marcia Gay. That's called reserve. Sometimes you don't need to throw your negative opinion out and correct all the wrongs," Harden said.  

Harden is also one of the stars of hit CBS medical drama, "Code Black." In it, she plays Dr. Leanne Rorish, the residency director who leads a team in a busy emergency room. The theme of the show's third season is also related to motherhood.

"For my character, Leanne, who is sort of a badass ER doctor and now she's attempting to adopt Ariel ... That's really an ER situation -- is raising a teenager. So she's got ER on both sides of her."

"Code Black" airs Wednesdays at 10 p.m. ET / 9 p.m. CT on CBS.