Jacintha Saldanha, 46, was found dead days after she transferred the call from two Australian DJs to a colleague who then described Kate's condition in detail.
It has now emerged she was being treated with anti-depressants and had made two attempts to take her own life during a family holiday in India, last December.
Jacintha Saldanha had made two suicide attempts previously, it is claimed
She was treated for depression and admitted to a psychiatric ward at Father Muller Medical College Hospital in
Mangalore, India, The Sun said.
Her brother Naveen Saldanha, 42, told the newspaper: “We didn’t know about the first incident, but we knew about the second.”
The news comes as it emerged Scotland Yard has submitted a file to the Crown Prosecution Service relating to the prank call.
The Crown Prosecution Service (CPS) will now consider whether any potential offences may have been committed, Scotland Yard said.
Ms Saldanha, a mother-of-two, was found dead in her nurses' quarters at London's King Edward VII's Hospital by a colleague and a security guard on 7 December.
king edward hospital
Saldanha worked at the King Edward VII hospital, where the Duchess was staying
Three days earlier she put through a call from DJs Mel Greig and Michael Christian, believing they were the Queen and the Prince of Wales.
Ms Saldanha left two notes in her room and was found with marks on her wrist when her body was discovered, Westminster Coroner's Court in London heard as an inquest was opened and adjourned.
Greig and Christian spoke of their grief on Australian television soon after the nurse's death.
They said their prank had prompted "a tragic turn of events no-one could have predicted or expected".
A Scotland Yard spokesman told the Press Association: "Following the death of Jacintha Saldanha, officers have liaised with the CPS as to whether any criminal offences had been committed in relation to the hoax call made to King Edward VII Hospital in the early hours of Tuesday 4 December.