Prince Harry and William were "lost souls" in their late teenage years before meeting Meghan and Kate, according to a royal expert.
Following the death of their mother Princess Diana, both of the dukes are said to have found supportive wives who helped provide them with the support that they needed.
Author Tom Quinn made the comments amid the release of his new book Gilded Youth, which studies the upbringing given to royals over the past few decades.
He believes that Harry and William being looked after by paid staff, in accordance with traditions, had an impact on both the princes because their hired nannies "could leave anytime".
Mr Quinn told the Express: "I think actually, in a strange way, the two boys, William and Harry, need their partners in a very similar way."
After describing the late Princess of Wales as "perhaps more modern and loving" than her ex-husband, the writer said: "So when their mother died, they had that terrible thing on top of the insecurity of being brought up by paid staff.
"I think by the time they reached adulthood, they both needed a woman who was either in the case of William level-headed and strong in that quiet, solid, secure way Kate has or, in the case of Harry, someone like Meghan who was going to grab him by the scruff of the neck and say 'this is the way to live'.
"But the end result was the same because the symptoms were the same. I think by the time Harry and William reached their late teens they were lost souls."
Earlier this month, Prince Harry directly acknowledged the impact that his wife, the Duchess of Sussex, had on his personal growth.
He told author Dr Gabor Maté: "People have said that my wife saved me. I was stuck in this world, and she was from a different world and helped draw me out of that."
But he pointed out that he was the one who made the change in his own life possible.
The duke added: "None of the elements of my life would have been possible without me seeing it for myself.
"It’s almost impossible to change other people, you’ve got to start with changing yourself and allow that growth to happen."
It comes as insiders tell the Mirror that Harry and Meghan are yet to make a decision about whether to attend the King's Coronation on May 6, which falls on their son Archie's fourth birthday.
The couple confirmed they have been officially invited, with their spokesman saying: "I can confirm The Duke has recently received email correspondence from His Majesty's office regarding the coronation.
"An immediate decision on whether The Duke and Duchess will attend will not be disclosed by us at this time."
During an interview with Tom Bradby on ITV earlier this month, Harry was asked if he will come to the coronation if he is invited.
He said: "There's a lot that can happen between now and then. But, you know, the door is always open. The ball is in their court.
"There's a lot to be discussed and I really hope that they can - that they are willing to sit down and talk about it, because there's a lot that's happened in six years. And prior to that as well."
