Defence counsel Joseph Markson said McArthur’s reaction was brought on by “undiagnosed and untreated” post-traumatic stress disorder (PTSD).

The PTSD comes from an accumulation of stresses, said Markson, with the sudden death of fellow officer Jennifer Kovach in 2013 really affecting McArthur.

McArthur had called for Kovach’s help while on duty and Kovach, on her way to help, died in a car crash.

McArthur felt “considerable guilt because he requested assistance,” said Markson.

McArthur had said that Kovach was “like a little sister to us on our shift,” said Markson. It was a heavy burden for McArthur to deal with, said Markson, and that year changed McArthur’s life.

McArthur, who has been on leave from work, has been getting treated for PTSD and has shown a commitment to recovery through effective treatment, said Markson, reading from a medical report.

The officer has accepted responsibility for the elbow incident but didn’t have intention to harm, said Markson, who spoke of “hypervigilance” and its relation to PTSD. McArthur reacted too fast and with too much force, Markson said. It was a case of clouded judgment due to mental illness and it resulted in human injury, he said.

It’s not the first time McArthur, 41, has faced criminal charges.

In 2010, Justice Elliott Allen convicted McArthur of assault in connection with a charge laid over the officer’s behaviour in a downtown bar disturbance call in 2008. McArthur was granted an absolute discharge and later pleaded guilty to discreditable conduct under the Ontario Police Services Act and had to work 10 days without pay as his penalty.

(In December 2012, McArthur was charged with assault causing bodily harm, stemming from a complaint from a private citizen. This charge was later withdrawn by the Crown in 2014 — the court was told there was no reasonable grounds for conviction.)

On Thursday, prosecutor Michael Carnegie said the 2010 circumstances cannot be ignored, that “impatience and intolerance” were on display both in 2010 and 2016.

Carnegie said: “The impatient reaction shares a resemblance to 2010.”

Incidents like these can have an impact on the public, he said. The public expects that when an individual is placed in police custody, that individual — no matter how difficult — will be in safe hands.

He said that it wasn’t the victim who reported the 2016 incident, it was hospital staff.

Carnegie said the video is an eye-opener. The victim was 17, handcuffed to a bed and vulnerable.

“The event is cringeworthy,” Carnegie said.

The crown is seeking a suspended sentence and probation in the case. The defence is seeking a conditional discharge and probation.

Sentencing is scheduled for Sept. 27.