After Bruce Willis' dementia announcement, Patti Davis remembers what it was like when her father, Ronald Reagan, publicly shared his Alzheimer's diagnosis

• In Bruce Willis' frontotemporal dementia diagnosis, Patti Davis saw similarities to her father's diagnosis.
• Davis' father, former President Ronald Reagan, publicly shared his Alzheimer's diagnosis in 1994.

The news of Bruce Willis' dementia diagnosis stirred difficult memories for Patti Davis, one of the daughters of former President Ronald Reagan.

Willis, 67, and his family announced last week that he has frontotemporal dementia, a disease with no treatments.

"I felt sorrow for Mr. Willis. I also felt a tug of fear about the consequences of going public — just as I felt in 1994 when my father told the nation that he had Alzheimer's," Davis wrote in an opinion piece for The New York Times.

Reagan's announcement of his diagnosis came five years after he left office in 1989. Davis wrote in the Times that she had "no clue what the world's reaction would be" at the time.

"I was amazed by his bravery in telling everyone he had a disease that most people didn't even want to talk about in those years. To my knowledge, no public figure had ever before revealed, in first person, that he had dementia," Davis wrote in the Times.

Reagan, who had already had colon cancer surgery several years earlier while in office, wrote in an address to the nation that he wanted to "promote greater awareness of this condition."

"I now begin the journey that will lead me into the sunset of my life," Reagan wrote in his 1994 letter to the public, according to the Ronald Reagan Presidential Library & Museum.

In the Times, Davis said her family received "a swell of sympathy and support from total strangers" during the decade he dealt with the disease.

"Not everyone, however, reacted with compassion. I learned to ignore the hurtful comments and the mockery, which continued to his death in 2004, at age 93," Davis said.

She added that she hopes the Willis family will have "a human wall of comfort to lean on."