04/25/2013 05:07 EDT | Updated 06/25/2013 05:12 EDT

"I Can't Believe I Caused So Much Suffering": An Attempted Murderer Relives His Crime

John Kastner

It's the part of the filmmaker's job I dread the most: screening the documentary for the subject of the film.

Today I am screening a film for Sean Clifton, who, in a psychotic state, tried to stab a complete stranger to death in in front of scores of witnesses because "...he wanted to kill the prettiest girl in the mall." He's the principal subject of my new documentary NCR: Not Criminally Responsible, which receives its world premiere at Hot Docs this week.

I have never been so concerned about a screening. In the past I have screened my films for murderers, serial rapists, pedophiles, but I am keenly that Clifton suffers from serious paranoid schizophrenia. You can still see a few residual signs of it despite the fact that his mental illness has dramatically improved after 13 years under the care of the Brockville mental Health Centre. He still broods over slights from decades ago. How will he react to seeing himself on film?

For one thing he is almost morbidly sensitive about his appearance. He was mocked about his looks as a boy in Cornwall and became convinced he looked like John Merrick, the Elephant man. They don't call it paranoia for nothing.

These screenings are one of the more harrowing moments for filmmaker and subject alike. For Clifton it means re-living the events of that dark night, the worst moment of his life.

So why subject him to this, you may ask? Because right now he feels his participation is so important, when forensic mental patients are being demonized as monsters in the media -- patients such as Vincent Li, the so-called bus be-header. In such a climate it is crucial the public see another face of forensic mental illness. Sean's face. For he is multo sympatico -- yes, despite what he did (see the film).

I have been trying to prepare for any possible negative reaction from Sean. I think I am ready.

I have been working closely with his psychiatrist and the rest of his treatment team since we first began with Sean around a year and a half ago. The team has seen the film, and believes he comes across well and can manage the experience. Sean has already said that he feels the experience of working on the film has been "therapeutic" for him; he is especially pleased that it has helped him reconcile with his victim.

Second: while he will have to watch the victim's excruciating memories of the incident, there are amazingly positive things about him in the film as well. Shawn White, the detective in his case, says of Sean, and others like him; "These are good people. I've seen it time and time again. He did a very bad thing but he's still a very good person. And that's why we can never give up on these people and that, because they are good people."

Senior nurse Sharron Capper adds: "Sean absolutely is a kind and decent person. It's the illness that is the underlying cause of the violence. Not Sean as a person. Sean is kind, genuine, honest. They're not born violent."

As for his fears about resembling John Merrick, the Elephant Man? He's actually not a bad-looking fella and (thank goodness) he photographs well.

Notwithstanding all this, there's one little nagging worry at the back of my mind: Even totally sane people react badly when they first see themselves in a documentary. For instance, people are often shocked at the expressions on their face when they talk and find it most disconcerting to watch.

We are now half-way through the screening. When Sean hears the victim describing years of pain she endured from the six stab wounds he inflicted, he sighs and says quietly: "I can't believe I caused so much suffering,"

The film is over, I hold my breath. Sean is subdued but seems OK. No apparent signs of trauma.

"Well?" says Shelley Siemons, one of his workers.

"I think that John did the best he could given the limitations he was working with," he says. I am relieved. He seems to be taking it well. We all go out for dinner. Sean is soon joking with the rest of us. He is nervous but excited that the film is coming out soon.

But two days later he phones me: "John, tell me the truth: "Do I look like John Merrick the Elephant Man?"

NCR: Not Criminally Responsible by John Kastner, National Film Board of Canada