According to a letter obtained by a UK newspaper, Mail on Sunday, the Queen's medical team feared Princess Diana had a genetic mental disorder that could have created a 'dynastic disaster' for the Royal Family.
In its latest issue, the paper published a letter written by Alan McGlashan, a well-known psychotherapist brought in to treat the princess during the 1980s.
Addressed to Prince Charles' close friend and advisor Laurens Van der Post, the letter details explosive information about Princess Diana's mental state.
At the time, the then 22-year-old Princess of Wales was being treated for anxiety, depression and bulimia by a team of palace doctors.
The team of medics assigned to the Princess were scared that her symptoms may cause 'dynastic disaster' and believed that her condition was genetic and would be passed on to her children.
McGlashan wrote that the palace’s medical team had dosed the princess, who had recently given birth to Prince William, with anti-depressants and sleeping drugs and were using 'behaviourist-techniques.'
However, the respected psychotherapist met the princess eight times and believed her to be 'a normal girl whose troubles were emotional, not pathological.'
The letter, which would generally be considered a breach of patient confidentiality by the then 84-year-old McGlashan, was uncovered during recent research being conducted for a biography of Van der Post.
Diana later went public about her mental health issues, telling the BBC in a ground-breaking 1995 interview with presenter Martin Bashir, that she had suffered low self-esteem and was aware that the palace’s doctors had tagged her ‘unstable’ as she struggled to cope with the pressure of joining the Royal Family.
She was just 20 when she married Prince Charles in July 1981, having only gone on 12 dates with the 32-year-old royal before he proposed.
Prince William and Prince Harry have carried on their mother’s work to make mental health a topic for open conversation, creating a charity called Heads Together to bring various mental health initiatives into discussion with each other. Harry has also previously reveled that he suffers from anxiety, and came close to a breakdown in his 20s.