The defence in the Philip Polkinghorne murder trial has called its last witness and finished giving evidence.
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Its final witness told jurors there is no way to know who will harm themselves.
The trial, which started in late July, was at the end of the seventh week of evidence and approaching the final stages.
Polkinghorne, 71, denies strangling and killing his wife Pauline Hanna at their Auckland home in 2021, and making it look like a suicide.
His defence is that he woke to find the 63-year-old already dead on Easter Monday.
Associate professor Sarah Hetrick, a psychologist, told the trial there was no way to predict suicide.
“The science is very clear about that,” she told defence lawyer Ron Mansfield.
“It’s impossible to predict who’s going to go on and take their own lives,” she said.
The Crown — from the outset of the trial — has argued Hanna committing suicide does not add up.
The defence in turn has highlighted Hanna’s long hours in a high-stress job and said she had earlier suicidal thoughts.
It also said she previously attempted suicide in the early 1990s, in evidence given by Hanna’s sister.
Drugs evidence presented
Earlier, another defence witness gave evidence on the drugs Hanna was using. They were both prescribed and not prescribed.
She was a long-term user of Prozac and the weight loss drug Duromine.
She had 67 scripts for the Prozac and 55 for the Duromine.
“It’s a restricted medicine for a number of reasons,” academic psychiatrist David Menkes told the trial at the High Court in Auckland.
He said it is supposed to be used by people who are seriously overweight.
“Which she wasn’t, and it should be used only for a maximum of three months, which it wasn’t,” he said.
Zopiclone, a sleeping aid, was also found in her system. She had no prescription for it.
This drug, Menkes said, carried “significant” risk.
He said it strongly interacts with alcohol to aggravate intoxication and the two should not be used together.
“There was clearly a risk that was present in her,” he said.
He said a combination of sleep problems, depression, anxiety, Zopiclone and alcohol would be expected to increase suicide risk.
“Whether they had that effect on that individual is not possible to say,” he said.
“But we can say with some confidence she had multiple risk factors at that point.”
At the end of seven weeks of evidence, at 12.26pm on Friday, Mansfield told Justice Lang the defence evidence was over.
The 11 member jury will return on Monday for the Crown to close its case.
