Overcrowded conditions fuelled by new federal laws that impose longer, stricter sentences will lead to more mental and physical health problems in prisons, a new report published in the Canadian Medical Association Journal suggests.

The study by Queen’s University law professors Adelina Iftene and Allan Manson says already crowded institutions will become more cramped as a result of sweeping legislation that includes more mandatory minimum sentences and tougher provisions on parole and conditional sentences.

Bill C-10 will have a "dramatic impact" on the size of the inmate population and stability of the institutional environments, according to the report.

"We can expect an aggravation of the current state of overcrowding, an increase in correctional costs, more young people in custody and prisoners spending longer periods in prison and being more isolated," the report says.

Under Canadian and international law, prisoners have a right to "the highest attainable level of health care," but the authors raise concerns that stretched resources could hamper the ability of physicians to deliver proper care.

Many inmates have not led healthy lives before incarceration, and face a new variety of stressors related to imprisonment such as culture shock, depression, exposure to contagious diseases and susceptibility to drug use. Rates of HIV and Hepatitis C are already dramatically higher behind bars compared to the community, and more overcrowding will likely worsen the spread of infectious disease, the report suggests.

Potential restriction of family visits as a result of C-10 may also have "devastating effects" on the mental and emotional status of prisoners.

"An increased number of prisoners run the risk of overwhelming an already overburdened system unless more is invested in mental-health care," the report reads.

Citing projections from the Office of the Correctional Investigator, the report says penitentiaries will need to accommodate 3,400 more prisoners by 2013. Ontario expects it will need to accommodate 1,000 more prisoners at a cost of $900 million and Quebec is expecting $600 million for new cells, according to the report.

"In an era of governmental budgetary restraint, is it likely that these allocations will be made?" the authors ask. "Regardless of new capital expenditures, it is reasonable to assume that increasing demands on correctional systems will affect allocations for internal programs, including health care."

The report also pointed to the Correctional Investigator’s link between overcrowding and an increase in violence, and said physically and mentally ill prisoners will endure greater fear of victimization and decreased safety.

But Julie Carmichael, spokeswoman for Public Safety Minister Vic Toews, rejected any link between overcrowding and violence behind bars.

"Double bunking is a completely normal practice used in many western countries. Correctional Service of Canada recently completed an analysis of prisons in the Prairies which found that violent incidents are independent from the levels of double bunking," she said.

"In fact, last year the number of double-bunked prisoners involved in violent incidents represented only one per cent of the total number of prisoners in the Prairie region. Correctional Service of Canada has concluded that double bunking has a minimal impact on the rates of violence in prisons."

Growth in prison populations has been only one-quarter of what Correctional Service of Canada had predicted and is far below what critics are claiming, Carmichael said.