Alex Ophel's lawyers say at the time of the alleged attack he was suffering from psychosis and delusional thoughts because of an undiagnosed mental illness.

Arguing for his release on bail, they said that illness was now being treated and the best place for him was a dedicated and secure mental health facility.

But prosecutors, opposing the man's release, said he had planned and executed the "frenzied" attack while no one had a clue it was coming.

They said it followed a series of disturbing internet searches.

Days before the incident, Mr Ophel, 18, looked up how easy it was to kill someone with a baseball bat, as well as ACT murder laws and life sentences, court documents say.

He had also searched "isis beheadings".

On August 25, Mr Ophel was allegedly yelling incoherently when he suddenly stood up during his Australian National University statistics class and attacked several students and the tutor with a metal baseball bat.

Another student intervened and Mr Ophel allegedly redirected his attack towards them.

Police arrived to students and security guards restraining Mr Ophel in a bloodied classroom.

There were five alleged victims.

Mr Ophel has pleaded not guilty by reason of mental impairment to four counts of attempted murder and one of intentionally inflicting grievous bodily harm.

His psychiatrists say he was suffering psychosis as a result of untreated schizophrenia around the time of the alleged attack.

The court heard his parents were unaware anything was wrong.

"This was all a shock to us," John Ophel told the court. "We were unaware of our son's condition.

"Alex all the rest of his life has been a gentle person, except for this psychotic episode."

In the ACT Magistrates Court on Thursday, lawyers for Mr Ophel asked the court to release him on bail to live at Brian Hennessy house, a residential mental health centre.

Defence barrister John Purnell SC said Mr Ophel's mental illness would be addressed more adequately at Brian Hennessy house.

Bree Wyeth, Mr Ophel's treating psychiatrist at the jail, said she believed Mr Ophel was a low risk of further violence and that the security at Brian Hennessy would keep him and the community safe.

She said if the community's greatest concern was the risk of violence the most effective way of reducing that risk was ongoing treatment.

She said he was responding well to medication in jail, but it was not the best place for him.

The doctor said Mr Ophel would receive more effective and intensive treatment at Brian Hennessy.

But prosecutors opposed the man's release, citing a risk he would endanger the safety of others and commit further offences.

Prosecutor Sara Gul said the risks to the community from Mr Ophel could not be remedied in any other way than custody.

She said this was on the background of Mr Ophel's explicit and horrific expressions of violence.

Mr Ophel told doctors that he had wanted to kill as many people as possible during the alleged attack and keep one woman alive and rape her, she said.

She said he had planned the attack, even choosing the class because it was mostly small women.

And the prosecutor said only five weeks ago he was still wondering whether he had a higher purpose of hurting people.

She disputed that Brian Hennessy house's security was adequate.

While it had "double-locked" doors and high-fences, Ms Gul said it had no "meaningful security" and people had escaped in the past.

Special Magistrate Margaret Hunter said she will hand down her decision on Mr Ophel's bail application on December 20.