Governments must make a "serious investment" in the mental-health system to prevent the vulnerable from ending up in prison, says a House of Commons committee that calls for co-ordinated action on a complex set of problems.
The public safety committee report says the federal prison service is "not able at this time" to provide adequate treatment and support to the majority of offenders with mental illness and addiction issues.
The MPs say offenders who do not receive the treatment and programs they need are more likely to commit crimes after release, compromising public safety.
They make 71 recommendations, including more special courts to handle the needs of people with mental-health and drug problems.
The committee urges additional federal money to allow the Correctional Service to fully implement its mental-health strategy.
It also recommends the prison service establish agreements with provincial psychiatric hospitals to transfer some offenders who pose a threat to themselves or others, but can't be treated at prison health facilities.
The agreements would include money and temporary correctional staff for the provincial hospitals.
Slightly more than one in 10 male offenders and one in five female offenders had serious mental-health problems when admitted to detention, numbers that have climbed substantially since 1997.
The federal prison ombudsman said last month that Canada's packed, crumbling jails - rife with illness, addiction and violence - are endangering the rehabilitation of offenders.
The Commons committee agrees with his assessment, saying the Correctional Service should give priority to quality care, treatment and programs for offenders with mental-health and addiction problems.
The MPs say this is "especially critical" given the anticipated increase in the federal prison population due to legislation that will put more people behind bars for longer periods.
Their report says although offenders admitted to the Correctional Service's regional treatment centres receive "adequate support," often they have to leave early due to a lack of space.
"As a result, many offenders once again find themselves in a state of psychological distress shortly after being returned to the general prison population," the report says.
This generally leads to prisoners being placed apart from others in conditions that only aggravate their mental health problems. "Successive or extended periods of segregation also reduces their access to much-needed correctional programs and services."
The committee also recommends the Correctional Service encourage the creation of drug treatment units in federal institutions.
The MPs say they realize the vexing problems go far beyond the prison service's mandate.
All levels of government must work together and, along with community partners, invest in a system based on mental health promotion, prevention and early detection and access to care and treatment, says the report.
The opposition parties had little expectation the government would implement the plan.
"I'm not optimistic with the Harper government. I don't think that they're committed to that," said NDP public safety critic Don Davies.
"They don't recognize the complex mixture of issues involved, they don't recognized that they're going to have to make a serious investment, and they don't recognize it'll take a little bit of time for these things to bear fruit."
The time for studies is now done, and there's a clear way forward, said Liberal public safety critic Mark Holland.
"I don't hold out a lot of hope this government is going to move on it," he said. "They're much more interested it seems in moving in the opposite direction, and doing things like double-bunking and expanding the prison population without putting any new resources in."
The Correctional Service did not return a phone call.
In a dissenting opinion accompanying the report, government MPs said significant resources have already been provided to the Correctional Service to support key elements of its strategy for dealing with the mentally ill, and noted the government has established the Mental Health Commission of Canada.
They also disagreed with the committee's approach to dealing with drug addiction in prisons, instead reiterating the government's zero-tolerance strategy.
"Illicit drugs in federal prisons compromise the safety and security of correctional staff as well as our communities. Providing needles, even if it is done under the guise of harm reduction, means putting a potential weapon in the hands of convicted criminals."
Public Safety Minister Vic Toews was unavailable. But his office said prisons should not be relied on to provide treatment for mental illness.
"We have achieved consensus with our provincial counterparts to ensure that the issue of mental health will be a standing item for future meetings between federal and provincial governments."