1 of 4 | (L to R) Then-Massachusetts U.S. Sen. Edward Kennedy (L) Joan Kennedy (M) and former first lady Jacqueline Kennedy Onassis in New York in March 1980. File Photo by UPI | License Photo

Oct. 8 (UPI) -- Joan Kennedy, a prominent U.S. mental health and addiction advocate, has died, her family said. She was 89 years old.

The first wife of the late Sen. Edward M. "Ted" Kennedy, D-Mass., Joan Bennett Kennedy died Wednesday in her sleep at her home in Boston.

"Besides being a loving mother, talented musician, and instrumental partner to my father as he launched his successful political career, Mom was a powerful example to millions of people with mental health conditions," her son, ex-U.S. Rep. Patrick Kennedy, D-R.I., said in the statement.

Kennedy's death was also announced by Massachusetts Democratic Party Chair Steve Kerrigan, according to The New York Times.