Philip Polkinghorne murder trial: Meth brings elevated risk of violence, jury hears

• Former eye surgeon Philip Polkinghorne denies killing his wife, Pauline Hanna, in April 2021
• Polkinghorne earlier pleaded guilty to possession of methamphetamine and a pipe
• The Crown argues a combination of financial problems, infidelity, and meth use led Polkinghorne to murdering his wife and stage her death as a suicide
• The defence argues Hanna killed herself after struggling with depression for many years.

Content warning: This story discusses suicide and domestic disputes.

A psychiatrist who specialises in addiction has explained the effects of methamphetamine use in the High Court trial of Philip Polkinghorne.

The retired Auckland eye surgeon has pleaded not guilty to murdering his wife, Pauline Hanna, in their Remuera home in 2021 and staging her death as a suicide.

Earlier in the week, the jury heard about a meth pipe with "sweet puff" written on the side, which was found at Polkinghorne's workplace.

Polkinghorne has pleaded guilty to possession of methamphetamine and a pipe.

And on Thursday, the jury was told that methamphetamine use could increase libido, energy and alertness, but also carried risks.

Addiction specialist psychiatrist Emma Schwarcz said someone who had taken meth might have wide pupils or eyes.

"They might be extremely alert, they might be aroused, they might be a little edgy, they might be tense, they might be, sort of, keyed up and pacing," she said

Schwarcz said a reduced appetite and loss of sleep were also side effects.

She said prolonged meth use could cause crashing withdrawals.

"As successive doses go on, there's less and less dopamine available to be released, as such, and then the unpleasant or adverse effects start to take over.

"So they're experiencing increasingly negative, unpleasant, agitating, dysphoric effects."

While most people who used meth were not violent, a range of studies showed elevated risk, she said.

"Even when controlling for past upbringing, past environment, and those past experiences, you're still 2.4 times more likely to have perpetrated violence if you'd used methamphetamine, compared with not using methamphetamine, and likewise, for intimate partner violence, it's 1.9 times."

Polkinghorne's defence lawyer Ron Mansfield KC asked about the difference between recreational meth users and those who suffer disorders from using the drug.

"What you've told us is that, whether methamphetamine has any of these impacts and the extent of those impacts, depends on the dose and how regularly they use the drug," he said.

"Yes," Schwarcz replied.

Margaret Skilton, a forensic accountant for the police financial unit, had previously told the court that Polkinghorne paid more than $100,000 to Sydney-based escort Madison Ashton.

On Thursday, Skilton was questioned by Mansfield about Hanna's spending in 2019.

"I just pulled off your data, of that there was $6647 on womenswear, $2595 on men's and womenswear, and then there was a healthy $8781 at department stores," said Mansfield,

Police constable Madeleine Palmer also took the stand to explain what was found on Polkinghorne's laptop.

"At 2.48am on the 2nd of April, a Google search was conducted for 'NZ escorts', and the following 11 minutes, through till 2.59am was spent New Zealand girls dot co dot NZ," she said..

Palmer told the court they had found emails between Polkinghorne and Ashton on the device, discussing moving furniture to Sydney.

Also on the laptop were videos of Polkinghorne and Ashton having sex, as well as multiple pictures of nude women.

Palmer was due to take the stand again on Friday.

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