A mother on trial had a "fixed, false and psychotic view" of her child's autistic condition and this "completely irrational belief was in the driving seat" when she smothered her with a pillow in their family home, her defence team have told a jury.
The Central Criminal Court trial also heard from a second consultant forensic psychiatrist, who said that the woman was suffering from severe depression with psychotic features and fulfilled the criteria for a special verdict of not guilty by reason of insanity.
The expert witness said the woman did not know the nature and quality of her act and believed her only option was to kill her daughter, who she was convinced was profoundly disabled and had no future or quality of life.
The two-day trial previously heard that the woman became "obsessed" and "overwhelmed" with her child's autism diagnosis and convinced herself that the toddler had a more severe form of autism - Pathological Demand Avoidance (PDA) - when in reality the diagnosis was at the milder end of the spectrum.
The woman described to gardai how she held the pillow over the child's face as she struggled and screamed on the couch in their family home. Her daughter called out for her daddy and finally let out a sigh, she said.
The woman, who cannot be named by order of the court, is on trial at the Central Criminal Court, having pleaded not guilty by reason of insanity to the murder of the three-year-old infant nearly two years ago.
The defence called Dr Stephen Monks, a consultant forensic psychiatrist from the Central Mental Hospital (CMH) today to give evidence on the mental state of the accused.
Dr Monks agreed with defence counsel Patrick Gageby SC that the woman was a dedicated and caring mother but her mood began "to dip" around the summer of 2017. The woman became "increasingly preoccupied" and "ruminated" about her daughter's health and this intensity heightened in the weeks leading up to the child's death.
The witness said that for the woman to come to the view that her daughter was profoundly disabled was completely removed from the reality of the situation.
On the day of the killing, her behaviour was profoundly influenced by her depressive state and she was consumed by a feeling of hopelessness and despair, continued Dr Monks. She was unable to generate coping responses and saw killing her child as the only solution, he explained.
In summary, Dr Monks said the woman is suffering from a mental disorder: severe depression with psychotic features. He said she did not know the nature and quality of the act as she believed her only option was to kill her child, who she was convinced was profoundly disabled and had no future or quality of life. She fulfils the criteria for the special verdict of not guilty by reason of insanity, he concluded.
A consultant forensic psychiatrist for the prosecution yesterday gave evidence that the defendant was suffering with "recurrent depressive disorder", which is a mental disorder and fulfilled the criteria for a special verdict of not guilty by reason of insanity.
Dr Sally Linehan from the CMH outlined that the accused did not know what she was doing was wrong and was unable to refrain from committing the act.
In his closing speech, prosecution counsel Paul Murray SC asked the jury to leave their emotion and sympathy aside in this very sad case. He suggested that the evidence in the case leads clearly and unequivocally to the special verdict of not guilty by reason of insanity.
This matter starts with a mother suffocating her first-born child and anyone looking at that would ask how can a "mother in her right mind" do that, he said. However, he asked the jury to consider the woman's history of mental problems, her obsession with the child's diagnosis and the apprehension she held for the future of the child.
Mr Murray said the view of both expert witnesses had reached the same conclusion that the defence of insanity was available to the accused "albeit by slightly different routes". He asked the jury to return a true verdict which reflected the evidence in the case.
Defence counsel Patrick Gageby SC said in his closing address that his client was a "gentle, kind and caring mother who lived for her children". She harboured a "fixed and false idea" that her child was suffering from the worst possible end of the autism spectrum disorder despite everyone saying to the contrary including the child psychologist.
The woman's "completely irrational belief" was in the driving seat when she killed her child, he said, adding that she had a "fixed, false, irrational and psychotic view" of her child's condition. "Her solution was not one that would lead anyone to consider a person was sane," he continued.
The barrister said that the woman has substantially recovered from her illness under the excellent care of the CMH. The evidence in this case points almost entirely if not entirely one way, said the barrister and he asked the jury to return a verdict that is supported by the evidence.
Ms Justice Carmel Stewart has finished charging the jury of six men and six women and they will commence their deliberations after lunch.