A court hearing into the mental competence of a mother accused of attempting to murder her two young sons on the side of an Adelaide motorway has been told she was delusional at the time, and that she told police she was "proud" of what she had done.
WARNING:This story contains content that some readers may find upsetting.
Megan Jayne Somerville, 37, of Modbury Heights appeared in the Supreme Court via video link from a mental health facility, but was not present when footage of the August 15, 2022, incident was played in court.
The court has previously heard Ms Somerville stopped her silver sedan on the North-South Motorway and removed her two sons, who were then aged three and eight, before stabbing them multiple times.
On Tuesday, the court heard she was experiencing an episode of psychosis, characterised by delusional thoughts, at the time of the incident, and had used both methamphetamine and cannabis in the hours beforehand.
The court is investigating whether her mental illness or her use of illicit drugs was the substantial cause of the offending.
Four videos were played to the court – including two of the incident itself – as well as body-worn camera footage from a police officer, and a video of Ms Somerville being read her arrest rights as she lay in a hospital bed.
Footage of the incident showed Ms Somerville repeatedly thrusting her arm at a child before another motorist stopped and intervened.
Footage from the body camera worn by a police officer as he arrived at the scene showed Ms Somerville wearing bloodied pants and giving her name to the officer, who repeatedly asked her what had happened.
"I'm proud of what I did," she said.
She could also be heard telling the officer she is bipolar and needed to go to a secure mental health facility, James Nash House.
A bystander could be heard telling the officer the knife had been moved away, while another bystander could be seen holding one of the children.
As ambulance officers take one of the children away, Ms Somerville could be heard repeatedly screaming that she loved her children.
"I love you my sons," she yelled.
The court today heard Ms Somerville did not wish to be present as the footage was played and her video link to the courtroom was disconnected.
She previously pleaded not guilty to two counts of attempted murder.
'Substantial amount of methamphetamine'
Forensic psychiatrist William Brereton, who interviewed Ms Somerville for three and a half hours, told the court he believed she had been experiencing worsening psychotic symptoms in the lead-up to the offence, including delusions about paedophiles, and that she believed her sons were aliens.
"I think as a result of her delusions, she felt compelled to harm her children because she loved them, because she thought she was saving them from a worse fate," he said.
"Her delusions were of such a nature that she then was compelled to act in that violent manner."
Dr Brereton said that, in his opinion, at the time of the incident Ms Somerville was mentally incompetent and "did not know that the conduct was wrong".
"There's evidence that shows that she was having psychotic symptoms for some months leading up to the offence and that those were perhaps fluctuating a bit," he said.
He said her use of illicit drugs would have also exacerbated her symptoms.
"The fact that she had a background of psychotic symptoms and then had a substantial amount of methamphetamine, and she was also chronically using cannabis, those all combined to give the picture that we saw at the time of the offence," he said.
He said her reasons for drug use were "complicated" and included a traumatic childhood and a degree of "self-medication" to relieve symptoms of mental illness, which was "under-treated" at the time.
The court heard Ms Somerville had since been treated with a medication reserved for use in treatment-resistant schizophrenia and had experienced symptoms for more than 12 months after the incident.
He said her "prolonged" symptoms meant her mental health was "unusually difficult to treat" but that she had engaged well in rehabilitation.
He supported a court finding that Ms Somerville be found mentally incompetent and said continued mental health treatment and rehabilitation would "better manage her risk" and provide better protection for the public.
The case will return to court on Friday.
