Warning: This story contains distressing details and discussion of attempted suicide

Lindsay Clancy, the Massachusetts mum who has been charged with murdering her three children, was suffering from a “command hallucination” at the time, a forensic psychiatrist has told the jury in her trial.

The defence, which rested its case on Friday, does not dispute that Clancy carried out the killings but say she has pleaded not guilty to murder charges because she was experiencing postpartum psychosis.

Forensic psychiatrist Phillip Resnick, the defence’s final witness, testified about the effects of postpartum psychosis.

Prosecutors, meanwhile, alleged she made a calculated decision to intentionally kill her children – Cora, five, Dawson, three, and Callan, who was eight months.

“My opinion is that Ms Clancy was, due to her mental disease, unable to conform her conduct to the requirements of the law on the day that she took the lives of her children,” Resnick told jurors. “It was a matter where she was just following the command rather than being able to make any decision to do it or not.”

The forensic psychiatrist said that in his opinion on the day Clancy killed her children she experienced “not only a command hallucination” but also “a delusion of influence”.

Resnick evaluated Clancy after the killings and reviewed her medical records.

Clancy lacked control and was likely unable to tell the difference between right and wrong on that January 2023 day, he told the jury on Friday.

“In her mind, she believed that she would be doing her children a favour by having them go to heaven with her rather than remain on earth without her doing the mothering,” Resnick testified.

The case is expected to go to the jury early next week following nearly a month of witness testimony.

Earlier this week, Clancy’s mother and former mother-in-law testified about how Clancy’s mental health deteriorated after the birth of her youngest son.

“She was begging for help,” Clancy’s former mother-in-law, Susan Clancy, said of a woman she described as a “very nurturing, very loving” mother.

Clancy has been charged with three counts of first-degree murder.

Prosecutors have said that in January 2023, Clancy intentionally strangled the three children with fitness bands in their Massachusetts home before jumping out of a second-floor window. Clancy, now 36, was paralysed by the jump and has attended the trial in a wheelchair.

The defence have said Clancy experienced hallucinations and delusions after giving birth to Callan and she was undergoing medical treatment for psychiatric problems. She checked herself into a psychiatric hospital for a few days just before the deaths.

The UK’s National Health Service (NHS) defines postpartum psychosis as a rare serious mental health illness that can affect someone soon after having a baby.

“Postpartum psychosis is very different from the ‘baby blues’,” the NHS adds. “It’s a serious mental illness and should be treated as a medical emergency.”

If you are suffering distress or despair and need support, you could speak to a health professional, or an organisation that offers support. Details of help available in many countries can be found at Befrienders Worldwide. www.befrienders.org.

In the UK a list of organisations that can help is available at bbc.co.uk/actionline.