Testimony concluded Wednesday in the trial of a Wagoner man accused of shooting an Arby’s employee in the arm.

Three witnesses took the stand as Kenneth Lynn Nickel’s defense told jurors Nickel was in the midst of a “psychotic break” when he shot Jamie Harbison at a Muskogee Arby’s on Sept. 28, 2010. Nickel is charged with assault and battery with a deadly weapon.

Curtis Grundy, a clinical and forensic psychologist, testified he believed Nickel “did not know the difference between right and wrong” when Harbison was shot. A prosecution witness — psychologist Terese Hall — disagreed, testifying it was her professional opinion Nickel knew right from wrong.

During cross examination, Grundy stated he did not know when Nickel lost the ability to tell the difference between right and wrong.

“Did he know right from wrong when he walked into the Arby’s?” Muskogee County District Attorney Larry Moore asked.

“I can say I believe his judgment was impaired,” Grundy replied.

When pressed by Moore, Grundy said he couldn’t “say with certainty” when Nickel lost and regained his ability to tell right from wrong.

Grundy testified Nickel had been prescribed Effexor and Trazadone — two common anti-depressants — before the shooting.

Grundy testified suicidal and homicidal ideations can be a side-effect of Effexor, and that during a psychotic break — such as the one the defense said Nickel endured — hallucinations can occur.

“It is a rare event, but it is noted in clinical literature that Effexor can cause this,” Grundy said.

Effexor and Trazadone had been prescribed to Nickel, Grundy said, because Nickel had been diagnosed with depression and anxiety. Post-shooting, Grundy diagnosed Nickel with bipolar disease and post-traumatic stress disorder, related to abuse issues from his childhood.

“He had clear evidence of mania,” Grundy said. “Manic episodes and hypo-manic episodes.”

Effexor, Grundy testified, can make a manic phase worse. Before the shooting, Grundy said Nickel told his prescriber he had no control over his moods. Nickel told Grundy his Effexor dosage was doubled at that point.

Nickel told Grundy the extra Effexor dosage made him “feel worse and more unstable.”

“He was taking extra doses of Trazadone and Effexor to calm himself, because he couldn’t sleep,” Grundy said. “He said he would pace in the garage and smoke all night because he couldn’t sleep.”

Grundy said the increase in Effexor dosage was “below the community standard of care.” When Nickel’s attorney, Thomas Mortensen asked Grundy if he would consider that malpractice, Grundy replied: “You could conclude that.”

Both sides will present closing arguments at 9 a.m. today, and the jury will be given their instructions from Associate District Judge Norman Thygesen before going into deliberations.

Reach Dylan Goforth at (918) 684-2903 or dgoforth@muskogeephoenix.com.