A leading psychiatrist does not agree that drug-induced psychosis can be considered a mental disorder resulting in someone being found not guilty of serious crimes by reason of insanity, the Central Criminal Court heard on Friday.
Prof Harry Kennedy, the former clinical director of the Central Mental Hospital, was giving expert evidence in the trial of James Kilroy, who has pleaded not guilty by reason of insanity to the murder of his wife Valerie French Kilroy.
The jury hearing his trial has been told Mr Kilroy accepts he killed his wife, who died from strangulation, blunt force trauma to the face and a stab wound to the neck. After the killing Mr Kilroy was seen walking naked in a field near his home and gardaí took him to Mayo University Hospital to be assessed under the Mental Health Act for admission to a psychiatric unit.
The trial has previously heard from Dr Ronan Mullaney, a consultant psychiatrist called by the defence, who said that Mr Kilroy was most likely suffering from cannabis-induced psychosis at the time of the killing and satisfies the criteria for the special “insanity” verdict.
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Dr Mullaney pointed out that two recent trials where the accused was diagnosed with drug-induced psychosis have resulted in that verdict.
Prof Kennedy on Friday told prosecution counsel Anne-Marie Lawlor SC that symptoms such as intoxication, withdrawal, delirium and psychosis are direct effects of cannabis use.
Under the Criminal Law (Insanity) Act, intoxication cannot be used as a criminal defence.
Prof Kennedy disagreed with Dr Mullaney’s finding that the accused was suffering from a schizophrenia-type disease caused by cannabis use. Schizophrenia, the professor said, is caused by functions within the body and brain over which the person has no control. Cannabis-induced psychosis would not happen without the use of cannabis, he said.
The professor said cannabis users and people with schizophrenic disorders endure different types of delusions and hallucinations. Those described by Mr Kilroy, he said, are not typical of schizophrenia.
Cannabis-induced psychosis, Prof Kennedy said, is a direct consequence of cannabis use whereby the toxins in the drug cause injured or damaged brain function.
In his conclusion, Prof Kennedy said the most straightforward diagnosis for Mr Kilroy is that he was undergoing a cannabis-induced psychosis. He said this does not meet the criteria for a mental disorder under the Criminal Law (Insanity) Act. It is important not to confuse mental illness with intoxication, he said.
He described Mr Kilroy as an “unreliable historian” who had, on occasion, denied memory of certain things before later recalling those things. He said there are “ordinary common-sense reasons” why a person might be inconsistent or unreliable, including that they are choosing to mislead or are malingering. He said such things are matters for the jury.
He also found that Mr Kilroy understood the nature and quality of his actions when killing his wife, knew that what he was doing was wrong, and was able to refrain from killing her.
Mr Kilroy (51) has pleaded not guilty by reason of insanity to murdering his wife at Kilbree Lower, Westport, Co Mayo, between June 13th and June 14th, 2019.
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