WARNING: This story contains graphic and sensitive content.

A High Court jury is hearing further evidence about Lauren Dickason’s mental state the day she killed her three children and in the weeks that followed after she was admitted to a secure psychiatric unit.

Dickason was “presenting with severe melancholic depression” and also had “ongoing ruminative thoughts”, telling one psychiatrist that she “would not hesitate to be given a lethal injection”.

The 42-year-old is on trial in the High Court at Christchurch facing charges of murdering her daughters Liané - who was a week from her 7th birthday - and 2-year-old twins Maya and Karla.

The sisters were found dead in their beds in September 2021 by their father Graham Dickason when he returned home from a work function.

The family had only been in New Zealand for a matter of weeks after emigrating from South Africa.

Dickason admits she killed the children but claims she was so mentally disturbed at the time she cannot be held responsible for the deaths.

Graham and Lauren Dickason with their daughters before the alleged murders. Photo / Facebook

The Crown alleges Dickason “acted methodically and purposefully, perhaps even clinically” because she was angry, frustrated and resented the children for the impact they’d had on her marriage.

“She knew what she was doing was morally wrong, and continued on her course, in any event,” Crown Prosecutor Andrew McRae told the jury last week.

Dickason has mounted a defence of insanity or infanticide, her lawyers saying she was a loving mother who had spiralled so deep into postpartum depression and was in such a “dark place” that she felt her only option was to commit suicide and take her children with her.

“All of the defence experts agree that there was an altruistic motive … That means that Lauren killed her children out of love,” defence lawyer Anne Toohey said.

“In her mind, she was killing them out of love - she was killing herself and she didn’t want to leave the children… she was so sure this was the right thing to do she persisted.

“This is about postpartum depression and a mother who killed her children. She did not want to leave her children without a mum… she also did not want her children to suffer from having such a bad mother.”

The Crown called witnesses to outline Dickason’s life and actions up until the alleged murders.

That included her long battle with depression, harrowing fertility journey and loss of a baby, fears about living in South Africa and the stressful emigration process and managed isolation period before the family arrived in Timaru.

Hours of messages sent to and received by Dickason about her apparent struggle with parenting the children were also shared, along with evidence of internet searches carried out on her phone about overdosing children.

The defence began calling witnesses this week, including Dickason’s mother and another relative.

Five expert witnesses will be called - three for the defence and two for the Crown.

The first is Dr Susan Hatters-Friedman, an international expert on “mental disorders flowing from all things from infertility to childbirth and beyond”.

Yesterday she outlined her own interviews with Dickason - spanning 10 hours.

Today she is giving further insight into Dickason’s state after the alleged murders - based on clinical notes provided by other psychiatric specialists who have treated her since her arrest.

She dreaded facing another day - expert on ‘desperate’ Dickason’s fatal spiral

“She said caring for her children was the hardest thing she’d ever done and... she found managed isolation overwhelming,” Hatters-Friedman said.

“She disassociated.”

Dickason had ongoing thoughts about hurting the children “in moments of stress and when lying in bed at night”.

“She was terrified to leave South Africa, but she was willing to leave South Africa,” the doctor explained.

“She dreaded facing another day.”

Lauren Dickason during her police interview. Photo / Pool

Dickason told one doctor that she was not hearing any “commands” to harm herself or her children - the thoughts were all her own.

“She was preoccupied with her inability to parent... she thought that she could not do another day,” Hatters-Friedman said.

“She just felt so desperate... she was tearful and distant... saying she didn’t want to be alive.

“She felt disconnected to her daughters... she said she was running on an empty tank all of the time.”

Dicksason was noted to have a “profound sense of hopelessness” and shared “an intense fear and worry something bad was going to happen” to her or her husband.

“For example, that they would get cancer or die in a car accident,” said Hatters-Friedman.

“Her thoughts of harming the children were in that context... she didn’t want the kids to grow up in a world with so many future problems.”

Dickason said at one stage that in the three months before she killed the girls: “I haven’t felt like I have been living in my own body, I have felt dead - no feeling. I feel like my soul had been pulled out of me.”

Hatters-Friedman said Dickason continued to have suicidal thoughts while at Hillmorton Hospital after her arrest.

She was caught at one stage with a number of items that could be used to self-harm or end her life.

“After a year [in Hillmorton] she opened up about her mental state and stressors at the time [of the alleged murders] ... she was feeling overwhelmed, she had no support, she felt she and the children were a burden to Graham.”

Expert’s formal opinion: Dickason was ‘labouring under a disease of the mind’ when she killed

At the end of her evidence, Hatters-Friendman gave her formal opinion to the jury as to whether she believed Dickason was insane at the time she killed her children.

“Her major depressive disorder began in her late 20s in the context of her reproductive struggles and her pregnancy loss… and she had been diagnosed with postpartum depression prior to the offending,” she said.

“At the time of the alleged offending, her depression had significantly worsened and she had developed psychotic features becoming out of touch with reality.”

Hatters-Friedman did not believe Dickason was “faking it” when it came to her mental state.

She said there was no evidence she was “malingering or feigning” her condition.

“Rather, she attempted to appear as if she was more mentally healthy than she was in the weeks leading up to the offending,” she said.

“She was able to feign or pretend that she was more well than she was immediately afterwards when she told the paramedics that she had not taken an overdose.”

Hatters-Friedman said the case was a clear example of an altruistic motive - where a parent kills “out of love” rather than out of anger or hate.

“She had been severely depressed and had developed psychotic thinking,” she said.

“She attempted to kill herself… she viewed the world as dangerous for her children to grow up in.

“She saw a joint suicide and filicide as a way out of this for her beloved children and herself… She thought she was getting her children to safety.”

Hatters-Friedman’s formal opinion was that Dickason committed a “murder out of love” based on a view of the world “through psychotic eyes”.

“It is my opinion that at the time of her alleged offending Lauren Dickason was labouring under a disease of the mind to such an extent that it rendered her incapable of knowing that the act was morally wrong,” she told the jury.

“Having regard to the commonly accepted standards of right and wrong, it is my opinion that her disease of the mind at the time of the offending was a major depressive disorder with mood-congruent psychotic features.

“She conceptualised that (killing the children) was the right thing to do.”

Infanticide - expert says Dickason’s mental disturbance direct result of childbirth

Defence lawyer Kerryn Beaton KC asked Hatters-Friedman to give her opinion of infanticide.

“It is my opinion that at the time of her offending Lauren Dickason was labouring under a disease of the mind to such an extent that it rendered her incapable of knowing that her acts were morally wrong,” she said.

“it is my opinion that she was experiencing a major depressive disorder with mood-congruent psychotic features.

“She described circumstances consistent with an altruistic motive for the murder of her children.

“It is further my opinion that at the time of her alleged offending, the balance of her mind was disturbed by reason of a disorder of consequence upon childbirth - specifically, she had been suffering from a severe depression which was closely tied to her infertility, pregnancy loss, postpartum and parenting.”

The trial continues.