"The Kennedy Curse." The 22-year-old granddaughter of Robert F Kennedy has been found dead.

With AAP.

Saoirse Kennedy Hill, a 22-year-old granddaughter of Robert F Kennedy, has died following an apparent overdose at the family’s compound in Hyannis Port, Massachusetts.

“Our hearts are shattered by the loss of our beloved Saoirse,” the Kennedy family said in a statement released to local media. “Her life was filled with hope, promise and love.”

The statement quoted her grandmother, Ethel Kennedy, as saying: “The world is a little less beautiful today.”

Saoirse was the daughter of Courtney Kennedy Hill, the fifth of Robert and Ethel Kennedy’s 11 children, and Paul Michael Hill.

A student at Boston College, Saoirse was a communication major and vice president of the Student Democrats.

The New York Times reported that she had written about struggling with mental illness while a student at a private school in Massachusetts in 2016.

Her depression, she wrote, "took root in the beginning of my middle school years and will be with me for the rest of my life."

The compound where Saoirse was found was a base during the presidential campaign of John F Kennedy in 1960, her uncle, and would later function as a summer White House.

The Kennedy curse

Following the 1969 Chappaquiddick incident, a car accident caused by Senator Ted Kennedy's negligence which claimed the life of 28-year-old Mary Jo Kopechne, Ted Kennedy said he wondered whether a "curse actually did hang over all the Kennedys".

The most famous tragedy to befall the Kennedys would be the assassination of John F Kennedy, the 35th President of the United States, in 1963. A sniper shot the President in broad daylight in Dallas, Texas, next to his wife Jacqueline Kennedy Onassis.

Five years later, in 1968, his brother Robert F Kennedy, then a U.S. Senator, was also assassinated.

John F Kennedy Jr., the son of John and Jacqueline Kennedy, died in a plane crash in 1999. He was 38 years old.

The curse, however, dates back further.

In 1944, Joseph Kennedy Jr. was killed in a plane crash during World War II at 29 years of age. Four years later, his sister Kathleen Kennedy, also died in a plane crash at 28 years old.

Joseph Kennedy was involved in a car accident in 1973 that left his female passenger paralysed for life. And there there were his two brothers.

A drug overdose was responsible for the death of 28-year-old David Kennedy in 1984. Michael was then killed at 39 years old in 1997 as a result of a skiing accident in Aspen.

There are a number of other illnesses and misfortunes that have touched the Kennedy family.

If you, or a young person you know, is struggling with symptoms of mental illness please contact your local headspace centre here or chat to them online, here. If you are over the age of 25 and suffering from symptoms of mental illness please contact your local GP for a Mental Health Assessment Plan or call Lifeline Australia on 13 11 14.