A woman who sued national water agency PUB, after she fell into a 1.8m-deep manhole five years ago, has added her diagnosis of schizophrenia in February this year to the list of injuries she allegedly suffered as a result of the accident.

Madam Chan Hui Peng, 47, believes her husband was an evil spirit and that laser beams were being shone into her condominium unit, her lawyer told the High Court yesterday.

Mr L. Devadason also told the court that his client, a chartered accountant, is no longer pursuing her initial claim of $20 million, which was based on the report of an accounting firm. She is now seeking about $5 million in damages.

She has submitted thousands of pages of medical reports and clinical notes in a bid to show that, apart from a fractured ankle and scrapes, the accident also caused her to suffer from post-traumatic stress disorder (PTSD) and schizophrenia.

PUB has accepted 70 per cent of the liability for the accident, but disputes her claims for items that include loss of future earnings and future medical expenses.

Lawyer K. Anparasan, acting for PUB's insurers, argued that Madam Chan "has a proclivity to obtain and amend medical evidence to her satisfaction". He said the defendant's experts will testify she did not suffer from PTSD and that "there might have been a degree of embellishment".

"(Madam Chan) has made a mountain out of a molehill and has seized the opportunity to capitalise on the injuries she allegedly sustained because of the accident."

He also noted surveillance by private investigators showed she could carry out daily activities, including walking up to 3.5km a day.

Mr Anparasan argued that she was "dishonest" in formulating her claim and had "concocted evidence with a hope of obtaining a windfall".

But Mr Devadason said Madam Chan was seeking "just compensation" for her physical and psychological injuries to "continue her diminished existence with at least some measure of dignity".

The court heard that on the morning of Dec 1, 2015, Madam Chan exited Kovan MRT station and was walking towards a row of shops to collect some birds' nest.

She did not see an open manhole near Kovan Residences and fell in feet first, landing on her buttocks. Mr Devadason said a tree had cast a shadow over the manhole and there was no cordon or signs around it.

Three PUB officers who were standing near the manhole helped her out and drove her to seek medical help. Madam Chan spent five days at Tan Tock Seng Hospital and was diagnosed with trauma, bruises on her hip and an ankle fracture. She then spent four months rehabilitating in a community hospital.

Her first complaint of a mental condition was recorded on March 17, 2016, when she told a doctor that she was fearful of holes.

That year, she visited the National Neuroscience Institute repeatedly for headaches.

She was diagnosed with PTSD after starting sessions at the Better Life Psychological Medicine Clinic on March 14, 2017.

In October 2018, she began filing police reports, complaining that people were talking about her or spying on her. In a report this year, she said she felt the heat from laser beams while she was on her bed.

She was warded at the Institute of Mental Health twice - once in February after she drank hand sanitiser, and in June after she threw a bamboo pole out of the window.

Yesterday, Madam Chan spoke softly but was composed when she was cross-examined on the stand.

Mr Anparasan contended that she was not working at the time of the accident and had concocted evidence to justify her claim for loss of earnings.

In her suit, Madam Chan said she earned $11,500 a month at HP&S International, which turned out to be a dormant family company.

The lawyer produced her pay cheque that she had signed herself.

He also produced a company letter, signed by her mother-in-law and typed by her husband Sim Kuang Jui on the day of the accident, putting her on no-pay leave.

On that same day, the company's registered address was changed from Madam Chan's matrimonial home at St Nicholas View to her mother-in-law's Bishan home.

Madam Chan disagreed the address was changed so that she cannot be linked to HP&S. She said the change was to make sure "the right person gets documents from the Government".

The trial continues.