Arguably one of the most outspoken royals, once Princess Diana ended her marriage to Prince Charles she regularly spoke on her ill-treatment by the royal family and how isolating the experience was.
"It was isolating, but it was also a situation where you couldn't indulge in feeling sorry for yourself, you had to either sink or swim. And you had to learn that very fast," she told Frontline.
Diana also wasn't one to shy away from speaking on her mental health - a trait her sons Prince Harry and Prince William would later adopt. Speaking on BBC's Panorama in 1995, she said: "I was unwell with post-natal depression, which no one ever discusses, post-natal depression, you have to read about it afterwards, and that in itself was a bit of a difficult time."
"I received a great deal of treatment, but I knew in myself that actually what I needed was space and time to adapt to all the different roles that had come my way," she added. "I knew I could do it, but I needed people to be patient and give me the space to do it."
The Duke of Sussex decided to step back from his role as a senior royal in early 2020, alongside wife Meghan Markle. But, even when he was a working royal he wouldn't shy away from tough subjects - including that no one actually wants the role of King or Queen.
He once told Newsweek, "Is there anyone of the royal family who wants to be king or queen? I don't think so, but we will carry out our duties at the right time."
Harry has also been incredibly open about his struggles with mental health since the death of his mother, Princess Diana. "I can safely say that losing my mum at the age of 12, and therefore shutting down all of my emotions for the last 20 years, has had a quite serious effect on not only my personal life but my work as well,” he said during a podcast interview. “I thought that thinking of her was only going to make me sad and not going to bring her back. So from an emotional side, I was, like, ‘Right, don’t ever let your emotions be part of anything.'”
He, along with the Duke and Duchess of Cambridge, founded Head's Together in 2016 - a mental health campaign that aims to end the stigma around mental health.
The Duchess of Sussex, since joining the royal family in 2017, admittedly struggled with how she was being treated by the press. Speaking to journalist Tom Bradby in a documentary about recent struggles she'd endured, she came close to tears.
"Look, any woman, especially when they're pregnant, you're really vulnerable, and so that was made really challenging," she said. "And especially as a woman, it's really — it's a lot. So you add this on top of just trying to be a new mum or trying to be a newlywed, it's..."
When Bradby asked if she was "okay", Meghan responded: "Thank you for asking, because not many people have asked if I'm OK. But it's a very real thing to be going through behind the scenes."
To this, Bradby asked: "And the answer is, would it be fair to say, not really OK? As in it's really been a struggle?"
"Yes," she responded.
In 2018, the Duke of Cambridge opened up about his time as an air ambulance pilot and the effects it had on his mental health.
"I took a lot home without realising it," he said. "You see many sad things every day that you think life is like that. You're always dealing with despair and sadness and injury. The attrition builds up and you never really have the opportunity to offload anything if you're not careful."
Like Harry, William has also previously spoken on losing his mother at such a young age. In the documentary, Football, Prince William, And Our Mental Health, the royal spoke with former football player Marvin Sordell about the emotions that followed having children.
"Having children is the biggest life-changing moment, it really is," he said. "I think when you've been through something traumatic in life, and that is like you say, your dad not being around, my mother dying when I was younger, your emotions come back in leaps and bounds because it's a very different phase of life."
"And there's no one there to, kind of, help you, and I definitely found it very, at times, overwhelming," he added. "I think emotionally things come out of the blue that you don't ever expect or maybe you think you've dealt with, and so I can completely relate to what you're saying about children coming along, it's one of the most amazing moments of life but it's also one of the scariest."