Jan 25, 2011 -- For years, Oprah Winfrey has promised her viewers shocking reveals on almost every episode of her show. But none was as extraordinary, especially to Winfrey herself, as finding out she has a half-sister.
The surprise was so great to Winfrey, who met her half-sister Patricia on Thanksgiving in 2010, that she said it "shook me to my core."
But while the public announcement and meeting of the two on her show Monday seemed like a joyous union, some experts said it may be because Oprah has had a few months to warm up to her new reality.
"It's a dramatic change in a person's life," said Dr. Howard Belkin, a psychiatrist affiliated with William Beaumont Hospital in Royal Oak, Mich. "That shock and disbelief comes in and you can't conceptualize it at first."
Not all who are faced with family secrets accept the news right away, if ever, according to some family psychiatrists.
In fact, despite three attempts by Patricia to contact her birth mother and Winfrey's mother, Vernita Lee, Lee refused to meet Patricia.
According to Belkin, the range of emotions following the announcement depends on the person's stage in life. Often, the older a person gets, the harder it becomes to accept a family secret, he said.
"[Winfrey] may have this regret of more than 40 years of never sharing her successes with [Patricia]," said Belkin.
Family Secrets: When to Keep, When to Spill
Winfrey's half-sister Patricia, a single mother of two, had been given up for adoption in Milwaukee, Wis., by Winfrey's mother in 1963.
"I was 9 years old at the time of [Patricia's adoption], living with my father in Nashville, Tenn.," Winfrey said. "I had no idea my mother was even pregnant."
While Lee chose to keep the secret from Winfrey for more than four decades, some may choose to come clean much sooner.
"This new generation of people shares their secrets much more freely," said Mary DeMuth, author of "Defiance Texas Trilogy," a three-book fiction series on family secrets, and her memoir, "Thin Places," which reveals her own secrets. "Nowadays people are much more apt to authenticity."
DeMuth's research into family secrets led her to create a blog where people can anonymously write about their family secrets. Since its inception in 2009, the blog has had nearly 300 postings of secrets revealed.
"I think people don't heal in the darkness, they heal in the light," said DeMuth. "My hope is that people will have a safe place to share something that's been on their mind for a long time."
When it comes to coming clean, every situation is different, said Belkin. But timing is everything.
"Every parent understands the maturity of their own child," he said. "[The child] has to be able to understand about relationships, love, and the concept that sometimes loving someone means you have to let them go."
In 2002, Allison Elliott, 36, of Temecula, Calif., chose to give up her fourth child, Sam, for adoption.
"We were in a really rough pivotal moment in our marriage and with our finances, and I felt like I needed to have him but not keep him," said Elliott, who chose an open adoption so she could still maintain distant contact with Sam.
Elliott said she did not plan to have any more children, but a couple of years after the adoption, she found out she was pregnant. While her three older children know about their brother, her youngest daughter Abigail, now 6-years-old, has no idea.
"We haven't been able to bring ourselves to share with her who he is. I'm not ready to share that with her. I think because as his mother and her mother I have that guilt that even though I'm so happy I made the decision I made, she came after him. And that's going to be hard to explain not only to Abby, but to Sam. That's the hard part for me," Elliott said, fighting back tears.
Although the family openly receives photos of Sam from his adoptive family, Elliott says Abigail thinks the boy in the photos is either a friend or a relative.
Eventually, Elliott says, she will have to overcome her guilt and tell Abigail. But not today.
Even if some take their time to tell, Belkin said, it's common for many children to feel betrayed.
"Some might say, 'If my parent never disclosed this major situation to me, what else may they have withheld from me?" said Belkin. That may bring anger, resentment, and mistrust, he said.
When Siblings Are Strangers
Winfrey has long considered her best friend, business partner, and confidante Gayle King as the "sister everybody would want," she told ABC News' Barbara Walters in a 20/20 exclusive interview last month.
And although Winfrey wanted to meet her biological sister Patricia, she said she was unsure what to do next.
"Some say you can't move on until you know the truth," said DeMuth. "But you have to ask, so what if you know the truth? You still have the decision to make of either moving forward or not."
Twilla Fontenot, 48, of Dallas, was 16 years old when she came home one day to find a stranger sitting at her family's kitchen table, whom her mother introduced as Fontenot's half-brother.
"People react to situations differently," she said. "When you have chaos in the household, when you have one more thing thrown at you, it just didn't soak in for me."
Until then, Fontenot had no idea her father had a son from a previous marriage. And it wasn't until nearly 20 years after that brief introduction that she decided to reunite with her half-brother.
"I was curious to know what he would be like. For some reason I really truly was hoping that my father would build a connection with his son," said Fontenot.
But it wasn't easy to build a relationship with her half-brother. And although she still sees him occasionally, she says she's unsure whether it brought the closure she thought it might. She feels much closer to her other siblings, with whom she was raised.
"When you haven't been raised with a sibling, there's not those connections, those memories and experiences you go through in life," she said.
And according to Belkin, although Winfrey was introduced to a blood-related sister, she may also feel more of an acquaintance or, at best, a friendship with Patricia.
"Siblingship is an emotional feeling as much as it is biological feeling. You can have a sibling relationship with someone who's not related with us and we can have a sibling whom we feel no relationship with," said Belkin.
While Winfrey seemingly embraced her sister within a few months of knowing, Belkin cautions others to take as much time as they need to decide how they will proceed once they know the truth.
"People love Oprah and care about her, and I think you know there's going to be pain involved," said Belkin. "And what she can do is what she's always done -- use this to help other people."