'I love writing and had planned to write a book some day, but this wasn't how I imagined it would come about,' Catherine Chong Shiu-yin said yesterday at the launch of her first book. The young United Christian Hospital psychiatrist's first book is not a medical text but was a form of psychological treatment after the death of her younger sister, Kitty Chong Chung-yin, a 19-year-old student who was crushed by a falling tree trunk in Stanley in August. The Chinese-language novel Walking Under the Deadly Tree, which records the effect of the tragedy on the Chong family, was a form of narrative therapy for Catherine Chong. 'The first two days I started writing, my heart raced, my hands shook, I panicked, I felt nauseous and lost appetite, and I couldn't fall asleep; they were all symptoms of anxiety,' Ms Chong said. 'But later, when I stopped escaping and I looked back at all the help that people have given us, all the good times we had with my sister, I felt different and was more able to detach myself from the pain.' Ms Chong's counsellor - the hospital's senior medical officer, May Miao Yin-king - had asked her to write a letter to her dead sister, but she wrote a book instead. It was completed and published in two months. RTHK programme host Tang Oi-lam, who wrote a preface for the book, said it was overwhelming. 'I didn't expect much, to be honest, but then I couldn't put it down,' she said. 'I was totally overwhelmed and stayed up all night to finish it.' The book tells how Ms Chong was wearing a T-shirt her sister had bought in advance for her birthday on the day Kitty was rushed to Eastern Hospital. Ms Chong said she was totally dumbfounded to see her little sister covered in blood. In another chapter, she tells of a mental patient who yelled at her in a lift on the first day she returned to her office, asking her to do some good deeds for her dead sister and release all her patients. The fatal accident sparked city-wide concern over tree management. Last month Chief Executive Donald Tsang Yam-kuen appointed Chief Secretary Henry Tang Ying-yen to oversee a tree safety taskforce.