Barbara Bush , the late former first lady who advised her husband and son during their presidential terms, privately faced a bout of depression, according to The Matriarch, a new biography to be released Tuesday.

USA Today Washington bureau chief Susan Page interviewed Bush in the months before her death last year, revealing part of her life she had shared only with her husband. For six months during the 1970s, Bush said, she felt depressed.

Page told CBS This Morning on Monday that Bush said she often found herself feeling so depressed that she had suicidal ideations while she was driving that were so strong that she would have to pull off the road and wait for the impulse to pass.

She told me that she felt she should have gone to a doctor, she should have gotten treatment, Page said, and that she would urge other people to [do so].

Apparently contributing to Bushs depression was that her husband, George H.W. Bush, became the head of the CIA and was unable to discuss his work, said Page. The changing social climate, with the growing feminist movement and expanding opportunities for women, added pressure.

At the time, to a small degree, she questioned the choices that she had made in life, Page said. She wondered if her life had real meaning, if she had made a big difference.

Page added that Barbara Bush said that when she confided in her son Neil Bush about her uncertainty, he was stunned that she carried such doubts, given her lifes work.

Barbara Bush died in April 2018 at 92 after suffering congestive heart failure and chronic pulmonary disease, eventually deciding to stop seeking medical treatment.

As first lady from 1989 to 1993, she championed early childhood education, establishing the Barbara Bush Foundation for Family Literacy to promote reading and writing. She is also remembered for having supported AIDS awareness and donated to cancer research along with her husband.

Former President George H.W. Bush died last November at 94. He had a series of health complications, including Parkinsons disease, a blood infection and bronchitis.

If you or someone you know needs help, call 1-800-273-8255 for the National Suicide Prevention Lifeline . You can also text HOME to 741-741 for free, 24-hour support from the Crisis Text Line . Outside the U.S., please visit the International Association for Suicide Prevention for a database of resources.