Wayne Treacy was likely in a hypnotic episode of mental illness when he brutally beat and nearly killed Josie Lou Ratley in March 2010, two medical experts testified Thursday during his attempted first-degree murder trial in Broward Circuit Court.

But the two psychiatrists — one testifying for the defense; the other for the prosecution — disagreed over the details of exactly when the Pompano Beach teenager entered that altered mental state, the severity of the episode, and perhaps most importantly for Treacy’s fate, whether he was conscious of his actions and their consequences.

“He was on autopilot,” Dr. Alexander Neumeister of New York University said of Treacy’s mental state during the attack. “What happened was completely outside any cognitive, intentional control.”

But Dr. Hans Steiner of Stanford University, called as a rebuttal witness for the prosecution, disagreed. He likened Treacy’s mental disorder, known as a “dissociative episode,” to the trance-like state that elite athletes enter when they focus intently on a goal and block out distractions.

“There’s no reason to think that he didn’t know what he was doing,” Steiner said, “and he didn’t know that it was wrong. It’s in his text messages.”

Treacy, 17, is presenting an insanity defense, and he faces a maximum penalty of 50 years in prison if convicted of the charges.

His attorneys have not denied that on March 17, 2010, Treacy walked up to Ratley on the campus of Deerfield Beach Middle School, threw her to the concrete pavement and repeatedly slammed her head against the ground and kicked her head while wearing steel-toed boots.

Ratley, 17, suffered permanent brain damage from the attack and will have difficulty creating any new memories for the rest of her life, according to doctors.

The two teenagers, both of whom were 15 years old at the time of the attack, had never met.

But they had exchanged a series of abusive text messages that escalated into violence after Ratley told Treacy to go visit his dead brother.

Michael Bell had hanged himself from a tree in the parking lot of New Covenant Church in Pompano Beach in October 2009. Treacy happened upon the scene on the way to celebrate his 15th birthday, and the image scarred him deeply, the doctors said.

Neumeister and Steiner agreed that Treacy suffers from post-traumatic stress disorder or PTSD, and that the mental illness was triggered by Treacy’s witnessing Bell’s suicide.

The doctors also agreed that Ratley’s comment was the cue that triggered Treacy’s dissociative episode.

Treacy already had been displaying classic signs of PTSD when he awoke before dawn on the day of the attack, Neumeister said, noting that lack of sleep is a common symptom. Treacy stayed home from school that day because of a “somatic” stomach ache that likely also was caused by his mental illness, Neumeister said.

That morning, Treacy received a text message from a girlfriend who had borrowed Ratley’s phone to contact him. Ratley disapproved of the relationship, however, and told Treacy so when she got her cellphone back.

The text message exchange quickly became abusive, with both teens insulting each other.

That’s when Ratley told Treacy to go visit his dead brother.