Adam Maier-Clayton says mental illness has ruined his life and he wants to die.

The 27-year-old Windsor, Ont., man suffers from depression, anxiety and a psychiatric condition called somatic symptom disorder, which leaves him in extreme pain with no clear physical cause.

“There is no cure for what I have,” Maier-Clayton told CTV News. “With modern science we don't understand mechanically what is going on inside of my brain.”

Maier-Clayton wants the federal government to make doctor-assisted death available to mentally ill people like him, who feel like they’ve exhausted all treatment options.

But the current law does not include people with mental illness. It allows assisted dying only for consenting adults "in an advanced stage of irreversible decline" from an incurable illness and for whom natural death is "reasonably foreseeable."

A review is underway to consider whether the law should be expanded to include the mentally ill, mature minors and people who want to make advance requests due to dementia or other “competence-eroding” conditions. The results of the review are expected in December 2018.

In the meantime, Maier-Clayton has taken on an advocacy role, speaking out against the restrictions in the assisted dying legislation and the limitations of the mental health system.

Despite trying numerous medications and undergoing extensive therapy, Maier-Clayton says nothing has restored the quality of life he had a few years ago.

A business school graduate who once had a promising future, he now relies on disability assistance payments and lives at home with his father.

“The only way he can really escape from the pain is by sleeping,” Graham Clayton said of his son. “Even then, at times it wakes him up.”

Clayton said most tasks -- even reading and talking -- exhaust his son to the point where he stays in his room for a day or two. Maier-Clayton suffers from headaches, burning sensations, and nausea, among other problems.

“It’s pain you can’t see, but it’s pain nonetheless,” Clayton said.

Working out briefly helps reduce his pain, but he has found no long-term relief.

“It’s very hard,” Clayton said. “(I thought) by this point in my son’s life he’d be starting his career and I could just sit back and enjoy watching him progress. And it’s just been the opposite.”

Clayton said he supports his son’s advocacy and believes that assisted-dying law should be changed to include the mentally ill.

“The people who are making these laws are people who’ve never experienced acute suffering,” he said.

“I don’t want my son to keep suffering, suffering, suffering…He is in pain and I believe him."

Mental health advocates are against assisted dying for the mentally ill, saying that most psychiatric disorders can be treated with proper, accessible care.

But that’s a problem in Canada, where mental health funding represents only seven per cent of the national health budget, compared to 10 or 11 per cent in many other industrialized countries.

When connected with the right support, advocates say even the worst cases of mental illness can be addressed.

“We believe recovery is possible,” said Rebecca Shields, CEO of the Canadian Mental Health Association’s York Region and South Simcoe branch.

“We see it happen every day when (patients) receive the right treatment and support and I hope that everybody receives that help and support.”

But for Maier-Clayton, the support he’s received so far made no difference.

“That’s the fact -- some people aren't going to get better, we don't have treatments for them,” he said. “And it is illogical to keep someone alive when they are suffering.”

With a report from CTV’s medical specialist Avis Favaro and producer Elizabeth St. Philip