TORONTO -- A man convicted of terrorism in a plot to derail a passenger train spat at lawyers and hurled a cup of water across a Toronto courtroom Wednesday after a psychiatrist testified that the man likely suffers from schizophrenia.

Chiheb Esseghaier vehemently expressed his disagreement with the diagnosis of Dr. Philip Klassen, thumping his chest and waving his hands in the air as he said the psychiatrist was being untruthful.

"You are lying," Esseghaier told Klassen. "Which delusion, which schizophrenia and which mental illness?"

Klassen told the court Esseghaier suffers from a mental disorder, but -- unlike the first expert who examined the man -- said the Tunisian national was still fit to be sentenced for his crimes.

Esseghaier and his co-accused, Raed Jaser, were found guilty in March of a terror-related conspiracy to commit murder and six other terror-related charges between them. Their sentencing hearing is currently under way.

During their last court session in July, the Toronto judge presiding over the case ordered a second mental health assessment for Esseghaier after concluding that an earlier one had "serious flaws."

In that first assessment, Dr. Lisa Ramshaw said she believed Esseghaier was unable to participate in his sentencing hearing because he is likely schizophrenic.

Klassen testified that while his diagnosis was similar to Ramshaw's in many respects, he still believed Esseghaier was legally fit to be sentenced.

"I would agree with Dr. Ramshaw that this gentleman suffers from a mental illness, in my opinion the best fit diagnostically would be schizophrenia," Klassen told the court. "I am not persuaded that he is not fit."

Klassen said that Esseghaier was aware of the nature of his court proceedings, understood their consequences and was able to communicate with the court in his trial.

Klassen repeatedly noted, however, that his assessment had to be conducted without interviewing Esseghaier because the man refused to meet with him. Klassen based his assessment on court documents, interview transcripts and Esseghaier's previous mental health assessment.

While it was hard to determine just when Esseghaier's mental illness developed, Klassen suggested Esseghaier was likely mentally ill in January or February of this year -- just before and during his trial.

Klassen also said that there appeared to be a consensus among those who knew Esseghaier before his arrest that the man's behaviour had changed over time, but whether that was the result of radicalization or the beginnings of a mental illness, or both, was unknown.

When asked whether he had any thoughts to share about Esseghaier's criminal responsibility in the trial, Klassen said he had wondered about the issue but hadn't formed an opinion on it.

Esseghaier, who is self-represented, is deeply religious and has consistently maintained his desire to be judged under the Qur'an.

He has often gone on rambling rants in the courtroom and even prayed in the prisoner's dock, but his mental state only became an issue in the case after Ramshaw's assessment -- which Esseghaier called a bunch of "lies."

Esseghaier lashed out at Klassen, as well as his own court-appointed lawyer on Wednesday, saying repeatedly that he wasn't mentally ill.

"I am similar to the Prophet Jesus and the Prophet Joseph. This is not mental disorder, this is the truth," Esseghaier said, while repeating statements which psychiatrists have called delusions. "We are before December 2014, because I am alive. If you say it's a delusion then the Qur'an is a delusion."

Esseghaier has said in court before that he believes he will die and his soul will be taken up to heaven on Dec. 25, 2014. Because that has not yet happened, he said he doesn't believe it is currently September 2015.

Justice Michael Code has previously said there was not "a scintilla of evidence" from the pretrial and trial record to suggest Esseghaier was unfit to stand trial.

He called Ramshaw's report on Esseghaier an "unsatisfactory psychiatric assessment" to which he could attach little or no weight.

Both Esseghaier and Jaser face the prospect of life in prison.

During their trial, court heard that an undercover FBI agent gained the men's trust and surreptitiously recorded their conversations.

The two were heard speaking about alleged terror plots they would conduct in retaliation for Canada's military actions in Muslim countries, including the derailment of a Via Rail train travelling between New York and Toronto.