Japanese Princess Mako diagnosed with PTSD before wedding to commoner

Japan's Princess Mako, the eldest daughter of Prince Akishino and Princess Kiko, and her fiance Kei Komuro at the press conference to announce their engagement in 2017. Photo / AP

Japan's Princess Mako has been diagnosed with complex post-traumatic stress disorder brought on by media speculation about her upcoming marriage to her commoner fiance, Kei Komuro, the Imperial Household Agency announced on Friday.

The agency confirmed that the princess and Komuro, a lawyer who works in New York, will be married on October 26, but said "abusive commentary" in the media about the princess and the family of her fiance has left her requiring treatment for PTSD.

Coverage in Japan's tabloid press has focused on reports that Komuro's mother borrowed Y4 million (NZ$52,000) from a former partner to pay the costs of his university education. She has allegedly declined to return the funds.

The couple were already in the full glare of the media when they announced their engagement in September 2017, only for the Imperial Household Agency to state that the wedding had been postponed after the financial allegations came to light.

Komuro later moved to New York to complete his law studies. Now 29, he works for a law firm in the city and returned to Tokyo on Monday to prepare for the wedding, although his arrival has triggered a new round of media speculation that has been amplified on social media.

Scholars and commentators have declared the wedding to be "the biggest crisis to threaten the imperial family in 100 years", while others have pondered the princess' fate if the marriage ends in divorce or accused the Komuro family of failing to act "with dignity".

Kei Komuro, fiance of Japan's Princess Mako, is escorted by security personnel as he leaves the Narita International Airport in Narita, last month. Photo / AP

The princess' decision to turn down the payment of Y150m (NZ$2.34m) that is traditionally provided to female members of the imperial family if they leave the household by marrying a commoner has attracted more headlines, while the couple are also expected to skip the formal Nosai no Gi engagement ceremony and Choken no Gi, an official meeting with the emperor and empress before the wedding.

The 29-year-old princess, who studied at the University of Edinburgh and later completed an MA at The University of Leicester, is expected to move to New York with her new husband shortly after the marriage is registered.

Her struggles with the media are an unhappy echo of the experiences of Princess Masako, the Oxford-educated commoner who married then-Crown Prince Naruhito in June 1993. The princess came under immediate pressure to produce a male heir to the Chrysanthemum Throne. It was only eight years later, however, that she became pregnant.

Excitement at the arrival of a healthy baby was tempered by news that the new arrival was a girl and therefore not eligible to assure the throne.

As a result of media speculation, Princess Masako suffered what the palace has termed an adjustment disorder and has rarely been seen in public since.

She is now empress alongside Emperor Naruhito. And although the couple have not had more children, the emperor's younger brother has solved the looming crisis for the world's oldest hereditary monarchy by producing a son who will eventually assume the throne.