She was diagnosed with schizophrenia in 2006, and had to stay at the Institute of Mental Health (IMH) three times between February 2011 and February last year.
In two of these occasions, Rebecca Loh Chui Lai, 32, was admitted into IMH after attacking her mother, Madam Kum Yuet Mei, 65.
And she was remanded in IMH once for carrying a chopper in a public place.
Despite her history of violence, Loh believed she was not mentally unwell and would not take her medication.
Her non-compliance with her treatment ended in tragedy.
She pushed her only child, nine-year-old Gabriel Loh Zhen Jie, out of the kitchen window to his death on June 1 last year.
The single mother was jailed the maximum 10 years yesterday, after pleading guilty to culpable homicide not amounting to murder.
Deputy Public Prosecutor (DPP) Eugene Lee said when Loh committed the offence, she was suffering from post-schizophrenic depression.
Gabriel was a sickly child and very small for his age, and DPP Lee said the boy suffered from a host of medical conditions including liver impairment that resulted in severe jaundice and malnutrition.
His father was Loh's acquaintance, and she lost contact with him before their son was born.
The mother-and-son pair had been living with Madam Kum in a fifth-storey flat at Block 704, West Coast Road.
The jobless Loh was financially dependent on her mother, a part-time assistant in a bakery, who earns $800 a month.
At around 6pm on the day of the incident, Loh was feeling very stressed about her finances and was worried about providing for Gabriel, the court was told.