The 2009 study, published Tuesday in the journal Open Medicine, identified 1,379 full-time psychiatrists in Ontario, then examined where in the province they practised and the number of patients they treated and how often.
Geographically, practices are divided among 14 LHINs, or Local Health Integration Networks, across the province. Some regions, such as Toronto Central and Champlain (which includes Ottawa), have a far higher concentration of psychiatrists than more sparsely populated areas, such as North Simcoe Muskoka and Erie St. Clair.
"One would assume that in regions with more psychiatrists, patients would have better access to care, as well as more timely care after being hospitalized," said lead author Dr. Paul Kurdyak, an emergency-care psychiatrist at the Centre for Addiction and Mental Health in Toronto.
"Instead, we found that in such regions, the opposite was true. A substantial number of these psychiatrists saw fewer outpatients, while their colleagues in low-supply, non-urban areas had more patients and more new patients."
The study found a huge disparity in the per capita number of psychiatrists, on a region-by-region basis. In Toronto Central, for example, there were 63 psychiatrists per 100,000 residents, compared to an average of seven per 100,000 in low-supply LHINs.
"People assume this is an urban-rural issue, but that's not the case," Kurdyak said in an interview Monday, noting that Mississauga, a sprawling, highly populated city adjacent to Toronto, was among the areas with a low supply of the mental health physicians.
"What was more striking was the way that the outpatient practice patterns changed as psychiatrist supply increased," he said.
"What we found was that the number of patients seen per year reduced as the number of psychiatrists per capita increased, to the point where in Toronto, the average outpatient volume was 181 and for the low-supply LHINs it was 431."
In higher-supply regions, the doctors tended to see fewer patients more frequently and often for longer-duration appointments, while low-supply-area psychiatrists saw their patients much less frequently, the study found.
But even within Toronto, there was a variety of practice patterns.
While the majority of psychiatrists had patient loads similar to their counterparts in low-supply regions, 10 per cent of those practising full-time hours in Toronto saw fewer than 40 patients a year, while 40 per cent treated fewer than 100.
In Champlain, 28 per cent saw fewer than 100 patients annually, while that was the case for 24 per cent in the Southwest LHIN (includes London, Goderich and Owen Sound). That compares to just 10 per cent of psychiatrists in non-urban regions who had a patient roster under 100.
These patients were seen more frequently and for longer visits, suggesting that they may have been receiving long-term psychotherapy, researchers said.
"The fee schedule in Ontario does not have limits on frequency or duration of visits, and does not say anything about the complexity of patients to be seen, so it may play a role in what we observed," said Kurdyak.
The study also suggests that income may affect access to psychiatrists, although equitable access for all is the linchpin of Canada's universal health system.
"We saw that no matter which LHIN you looked at, there was a relationship between the neighbourhood income level and visit frequency," said Kurdyak. "So the more frequently you were seen, the more likely you resided in a high-income neighbourhood. And the most extreme was that the 44 per cent of patients who were seen more than 16 times per year were from the highest income quintile."
However, he noted, the data can't say whether patients from wealthier areas had a greater need to see a mental health professional than those from lower-income neighbourhoods.
Disturbingly, researchers found the likelihood of being seen following a psychiatric hospitalization — which Kurdyak calls a "real period of need" — is only slightly higher in the high-supply regions than low-supply areas.
"You want to see 100 per cent of the people," Kurdyak said. But among those who had been hospitalized for schizophrenia or bipolar disorder, less than half were seen by a psychiatrist for followup care within 30 days of discharge. In Toronto, for instance, 17 per cent of those with schizophrenia were back in hospital within a month of discharge. At six months, 40 per cent were rehospitalized.
Dr. Gary Chaimowitz, president of the Ontario Psychiatric Association, welcomed the study, saying it provides critical data that will aid the OPA's and other organizations' efforts to improve availability of care.
"We know access to psychiatric care is probably the biggest issue right across the country, and that is our challenge," Chaimowitz, a forensic psychiatrist at McMaster University, said from Hamilton.
"And clearly we don't think minting more psychiatrists will resolve that issue. But we definitely believe there are not enough psychiatric services and there's not enough funding for mental health care in this country."
Chaimowitz said there are many models of care to boost access, some already in practice, including psychiatrists working as members of primary-care teams.
Telepsychiatry — providing counselling and care through computer-based communications devices — can help patients in remote regions receive treatment, added Kurdyak. There also could be incentives within the current fee-for-service model, which the study looked at, which could perhaps encourage underutilized psychiatrists to swell the number of patients they see.
He said the study shows that training more psychiatrists is not the answer for resolving the lack of patient access.
"The larger picture is how can we deploy the relatively large number of psychiatrists in Ontario in such a way that the needs of all the people who need specialist psychiatric care can access it equitably?"
— Follow @SherylUbelacker on Twitter.