By 1999-2000, the number of treatments had risen to 1,533, with an average of slightly more than four electric-shock sessions per patient. The hospital is already conducting its own internal review of the frequency of electroconvulsive shock therapy (ECT), as the procedure is formally known.

However, a Health Ministry spokeswoman said Mr. Evans has asked the ministry to appoint "someone independent who doesn't work at Riverview to go in and take a look at what's going on there." She said the appointment would be made as soon as possible.

In his letter to Mr. Evans, staff psychiatrist Jaime Parades noted that the number of ECTs ordered for other Riverview patients had remained stable over the past four years, while ECT procedures at comparable institutions had stayed the same or decreased.

"Meanwhile, the number of ECT treatments in the Geriatric Psychiatry Program at Riverview Hospital has more than doubled since fee-for-service was introduced," Dr. Parades told the Health Minister.

He said attempts to raise his "grave concerns" with hospital administrators have been met with "roadblocks, delay tactics and intimidation."

Electric-shock treatment is a controversial procedure to be used only as a last resort on psychiatric patients suffering from serious depression or mania who do not respond to more conventional treatment.

It is administered under a general anesthetic and uses an electric current passed through the brain to provoke a seizure in the central nervous system. For reasons that are not clearly known, ECT has been shown to benefit as many as 50 per cent of patients in certain circumstances, although some mental-health advocates consider the treatment extreme and barbaric.

"I don't generally do ECTs," said Dr. Parades, who has worked at Riverview for 15 years. "But I don't have a problem with the procedure itself. Sometimes it works. Sometimes it doesn't.

"My problem is that I could not get answers or due process when I asked why the volume went up when extra payment for the service was introduced."

Staff members at the hospital who raised the issue have been punished by losing managerial positions and not having their Riverview contracts renewed, Dr. Parades charged in his letter, sent last week.

"I am approaching you as a last resort in an effort to achieve accountability," he told the Health Minister, adding that he believed he was risking his career by speaking out. "I feel the machinery and wheels of bureaucracy are slowly grinding this matter into obscurity. But it is real people who are affected, patients with no power and with no voice." Riverview spokesman Alastair Gordon said there are two reasons for the significant increase in ECT at Riverview. "We are accepting referrals from other hospitals, and there is growing medical acceptance of ECT as a treatment of choice for geriatric patients suffering from depression."

Mr. Gordon pointed out that the doctors who perform ECTs at the hospital and receive the extra payment are not always the same psychiatrist who prescribes the treatment. He added that the hospital is not concerned by the minister's decision to launch an independent investigation into the controversy.

However, Mr. Gordon said colleagues at the hospital are dismayed that Dr. Parades chose to "go outside the process and talk to the minister. Our doctors would have preferred he stay with our own internal review." The province's investigation will look at both the appropriateness of treatment prescribed for the geriatric patients and the question of ECT billings under the provincial health plan.

Riverview, with more than 800 patients, is one of Canada's largest psychiatric institutions.