Defence-witness pharmacology expert testifies Jason McKay had alcohol-induced amnesia

A pharmacology expert testified Friday that he believes Jason McKay suffered from alcohol induced amnesia, but noted he was forming some of his opinion based on what McKay said.

McKay is on trial at Regina's Court of Queen's Bench, accused of fatally stabbing his wife Jenny in 2017. He pleaded not guilty to second-degree murder.

Steven Richardson, a pharmacology expert, was called to testify as an expert by the defence. 

Richardson said McKay was unable to appreciate the consequences of his actions when he allegedly stabbed Jenny because of alcohol-induced amnesia — sometimes called blackouts.

Richardson suggested a combination of Sertraline (an antidepressant) and alcohol led to this state. McKay testified Thursday that he took antidepressants daily and that he drank four cans of Twisted Tea and some red wine on Sept. 5, 2017.

McKay said that after his first sip of red wine he began to experience multiple blackouts. He said he remembered stabbing his wife twice with "a dagger" after hearing voices, although no "dagger" was recovered from the crime scene.  

Richardson said there are no scientific studies on how Sertraline might act affect the blood alcohol level, but he was confident there would be some sort of interaction. 

"If someone's in an amnesia period, they would have no judgment," Richardson maintained under cross examination on Friday. He said that's because brain cells responsible for creating long-term memories are also involved in judgment.

Richardson said people are still capable of thoughts, ideas and plans in an alcohol-induced amnesia state, but plans would be carried out without an "appropriateness filter." 

When asked by the Crown to point the court to the scientific evidence to back that up, Richardson he couldn't. He said his opinion was based on an understanding of brain functioning. 

McKay testified his blackouts extended to his time with police after his arrest. He said he couldn't remember police interviews on the eve of Sept. 6, or the next morning.  

Richardson said it's possible McKay was still suffering from alcohol-induced amnesia during the evening — about 13.5 hours from the time McKay was arrested. He admitted he had been assuming that McKay continued to drink wine.

"Are you just assuming things that tend to favour Mr. McKay's recollections?" asked Crown prosecutor Adam Breker. 

"I do not know scientifically whether he was suffering," Richardson said, adding he was relying on McKay's behaviour after he was told Jenny was dead by a police officer, which he felt was consistent with someone who could not remember. 

"I have to take his word for it." 

However, Richardson did say he didn't think McKay would still be suffering from the amnesia on the morning of Sept. 7, 2019  — an interview McKay said he cannot remember. 

Richardson said there is not yet scientifically acceptable means to assess if alcohol induced amnesia has occurred, so the only way to know is to talk to someone and ultimately trust their account. Closing arguments are expected to take place on Monday afternoon.