In a letter to the New York Post, Kerry Kennedy, the best friend of the late Mary Richardson Kennedy and sister of Robert F Kennedy, Jr, details how Mary was a victim of a debilitating depression which eventually drove her to suicide.

Kerry Kennedy bluntly opens her saying, “If difficult divorces caused people to commit suicide, nearly half the adults in America would be dead.” There are many who believed Mary and RFK Jr’s divorce, coupled with his newly public relationship with actress Cheryl Hines, may have driven Mary to take her own life.

Kerry Kennedy had been best friends with Mary Richardson since the two were teenagers and writes fondly of the vibrant, talented and beautiful Mary she knew. It was Kerry who introduced Mary to Robert F Kennedy, Jr. The two were later married, had four children, but divorced in 2010.

“For six agonizing years,” writes Kerry Kennedy of Mary, “she embarked on an odyssey so harrowing that Dante himself would tremble at the courage of that tender, luminous woman who walked through the mouth of hell.

"She endured unbearable pain for her children and the people she loved.

"She fought the impulses and kept herself alive.”

Of Mary, Kerry writes “She had a wonderful life with brilliant children, a successful career as a designer, and deep and abiding friendships with people across the globe. She had won life’s lottery over and over again. She was my best friend for 37 years. But since the day I met her, she battled periodic depression.”

“Mary didn’t ask for this disease, she never deserved it, and she took every step, from those prescribed by doctors to looking to God, to try and find a way out of it. Mary recognized part of her was broken. As her husband, my brother Bobby, who spent years and untold efforts trying to rescue her from her depression, said in his eulogy, Mary would be distressed to know so many of her friends feel they should have done more to save her.”

While Kerry admits that her best friend’s suicide is a “personal tragedy,” she hopes that Mary’s death and the hands of depression will grow into a message for the public. “I hope Mary’s struggles will inspire more of us to join the national efforts to address the causes and cures of depression.”

Concluding her public letter, Kerry addresses the slighted public understanding of those who suffer from depression: “When people say there is a ‘reason’ for the depression, they insult the person who suffers, making it seem that those in agony are somehow at fault for not ‘cheering up.’

"The fact is that those who suffer — and those who love them — are no more at fault for depression than a cancer patient is for a tumor.

"And the first step is for us to be honest about who Mary was, and try to understand the painful reality of the agony of her depression and her decision to end her life.”