The association, which consulted with the Canadian Academy of Psychiatry and the Law, spent more than two months examining the government legislation before weighing in with an assessment.
Their critique boils down to the legislation being unnecessary, counter-productive and costly, and that it may be vulnerable to a challenge under the Charter of Rights and Freedoms.
Prime Minister Stephen Harper announced the changes in early February during an emotional news conference in Vancouver where he cited a horrific case in which a mentally ill father killed his three children.
The law would create a new high-risk category that would hold mentally ill offenders longer without a formal review and make it far more difficult for them to leave psychiatric facilities, even under escort.
"The government is confident that the proposed reforms are reasonable and necessary to protect public safety and ensure public confidence in our justice system," Julie DiMambro, a spokeswoman for Justice Minister Rob Nicholson, said Thursday in a email.
Mentally ill offenders "will continue to receive treatment and have their cases overseen by independent courts and review boards."
But the Canadian Psychiatric Association said it believes it is "highly likely" the new law will prompt the mentally ill to keep quiet about their problems and simply serve their time, only to emerge from prison untreated and five or six times more likely to reoffend.
Several gut-wrenching, high-profile homicides involving mentally ill perpetrators galvanized public opinion and spurred the Conservative government to wade in with new legislation.
Justice Richard Schneider, chairman of the Ontario Review Board, noted in a recent letter to the editor that Allan Schoenborn, Vincent Li and Guy Turcotte were not part of the NCR system when they committed their infamous crimes.
He accused the government of "sleight of hand."
"What the proponents have done is taken extremely horrific 'outlier' cases involving people who committed their offences prior to obtaining verdicts of NCR (and entering the review board system) as oblique indictments upon the provisions ... which govern them after the verdict is obtained," wrote Schneider.
Those outlier cases show problems with the mental health system — not with the rules for handling NCR offenders, he added.
"The safest place for an offender to be in Canada is subject to the jurisdiction of a provincial or territorial review board."
The government changes also include mandatory notification of victims when NCR individuals are released, a measure the Canadian Psychiatric Association said it supports.
However the association noted that tracking and communicating with victims will require additional resources and will also likely delay the release of NCR patients, tying up mental health beds. And it said not all victims "wish to remain engaged in the offender's release process, experiencing it as a revictimization."
As for designating some NCR offenders "high risk," the association cited a long list of concerns, starting with the observation that it was "not aware of any evidence that demonstrates that the current NCR policies put the public at undue risk."
It states that the new category "is unlikely to achieve its goal of increased public safety but will be a substantial drain on resources."
And it worries that by introducing "retribution" into the NCR system, patients will be "less engaged in their therapy, paradoxically, increasing public risk."
The association called it "unfortunate" that the rhetoric being used to support the legislation comes at a time when the Mental Health Commission of Canada is trying to reduce the stigma of mental illness.
The psychiatric association is just the latest of several professional groups that work with mentally ill offenders that have come out against the legislation.Suggest a correction