The jury has previously heard that an issue in the trial is whether Ms Anderson's actions were driven by mental illness or cannabis intoxication
The jury has previously heard that an issue in the trial is whether Ms Anderson's actions were driven by mental illness or cannabis intoxication when she repeatedly stabbed Gareth Kelly as he tried to start his car outside her home .
Dr Johann Grundlingh, who was called by Ms Anderson's defence, said the effects of cannabis typically last from one to three hours.
He said if it is true that Ms Anderson smoked her final cannabis cigarette at about 10pm the previous evening and stabbed Mr Kelly at about 7am, it is "extremely unlikely she would still have been intoxicated with cannabis".
Dr Grundlingh told defence counsel Michael O'Higgins SC that cannabis intoxication does not explain her behaviour on the morning of the stabbing or in the subsequent weeks, during which she was transferred to the Central Mental Hospital (CMH), where she was found to be acutely psychotic.
Ms Anderson (41), a mother-of-three, of Brownsbarn Wood, Kingswood, Dublin 22, is charged with murdering Mr Kelly (39), who was stabbed five times as he tried to start his car outside her home on the morning of February 25, 2020. She has pleaded not guilty by reason of insanity.
Dr Brenda Wright, a forensic psychiatrist and interim director of the CMH, previously told the trial that Ms Anderson has bipolar affective disorder. Dr Wright said that as a result of her disorder, Ms Anderson falsely believed Mr Kelly was a danger to herself and her family and that by stabbing him, she was protecting them.
She said Ms Anderson's mental condition also made her unable to refrain from stabbing Mr Kelly.
Under cross-examination today, Dr Wright told prosecution counsel Patrick McGrath SC that in coming to her findings, she had considered all the information available to her.
Mr McGrath said that another psychiatrist, Prof Harry Kennedy, who will be called to give evidence by the prosecution, found Ms Anderson to be an "unreliable historian".
Prof Kennedy's report noted that Ms Anderson had given "wholly different" accounts of why she killed Mr Kelly to different people.
Dr Wright agreed that Ms Anderson had said that she killed Mr Kelly because she believed he was a danger to herself and her family, while on another occasion she said she did it because she believed illusionist Derren Brown was telling her to stab him so she would become famous.
Mr McGrath said that in the section of Dr Wright's report dealing with the reasons why Ms Anderson committed the stabbing, she had not referred to Ms Anderson believing she was being directed by an illusionist.
Dr Wright said she did not deal with that in the conclusion but had dealt with it in her report. She said that her conclusion that Ms Anderson falsely believed she and her family were in danger was based on a review of all the information available to her.
She said she looked at the statements of Ms Anderson's family, friends and neighbours, who described her as being in a state of fear in the days leading up to the stabbing.
Dr Wright denied that she had "dismissed" the alternative explanation or that she had "plumped" for one explanation and ignored the possibility that Ms Anderson might have been lying.
"I have considered all the information available to me and have drawn a conclusion which I have outlined clearly," she said.
Dr Wright's cross examination will continue on Monday in front of Ms Justice Karen O'Connor and a jury of seven men and five women.