Schapelle Corby may inhabit a filthy, rat-infested concrete cell in the hellhole that is Bali’s Kerobokan Prison, but she lives in a world of fantasy. She hears voices in her head. Statues tell her secrets. Non-existent birds twitter and stop to send a secret code and imaginary ducks tell her to follow them.

Several weeks ago, one of these ducks led Schapelle, 32, onto the roof of her cell block. It was high and dangerous. She had climbed into the ceiling from inside her cell, then lifted tiles from the roof and climbed out. In her imagination, the duck was telling her to follow it to the beach. She was coaxed down safely, but she’s since done it again. The second time, the duck was telling her to come up on the roof to get some fresh air.

In her more lucid moments, Schapelle doesn’t want to deal with the hell of prison life anymore. She has slashed her wrists twice and told Australian psychiatrist Dr Jonathan Phillips, who recently examined her, that if she bleeds to death, she doesn’t care who is left to clean it up. It’s a stark turnaround from three years ago, when she told me, while I was writing her biography, that she was totally against suicide because she felt it was selfish to leave behind a mess and trauma for family.

But in the past 18 months, Schapelle, a former Gold Coast beauty-therapy student jailed on October 8, 2004, for smuggling 4.2kg of marijuana into Bali, has changed indescribably.

I caught up with her recently while working on my latest book, Hotel Kerobokan: The Shocking Inside Story of Bali’s Most Notorious Jail, published by Pan Macmillan Australia on November 1, and found her dishevelled, childlike and teary, with sores and scratches on her face and knees. The black hole that she has been slowly sliding into since she started her 20-year sentence has now finally consumed her. Much of the time she is disconnected from reality, which is simply too painful for her to bear.

For the first three-and-a-half years inside Kerobokan Prison, she somehow held it together, despite being kept in a place most people would not think fit for a dog: she once found a bloody sanitary pad draped over her toothbrush, rats run around in her cell, junkies have injected themselves next to her, women have almost died from miscarriages in her cell, she has witnessed brutal bashings and a prisoner hanging by a noose. She lives in a small concrete cell with up to 15 other women. The squat toilet often blocks and spews out raw sewage. The door is locked at 4.30pm and not opened until 7am.

Incredibly, when she came out to visits, she was usually upbeat, immaculately dressed and groomed. Yet, despite how normal she seemed, staying positive took enormous willpower and effort. Schapelle did it for herself, but mostly she did it for her family and particularly her dad, Michael, who was prone to his own bouts of depression due to having bone cancer.

However, Schapelle was coping by repressing her pain and shutting down.

Eighteen months ago, Schapelle told me she wanted to die. The chilling words came after I’d asked her if she was okay. “No I’m not. I want to die.”

“No you don’t, Schapelle,” was my reflex reply. She turned and looked directly at me with her piercing blue eyes. “Don’t ask me if you don’t want to hear it … I do want to die.”

Read the rest of this compelling story in the November issue of The Australian Women’s Weekly out now with Sarah Murdoch on the cover.

Your say: What do you think of Schapelle? Do you think she should be brought home?