It is unlike any other treatment in psychiatry, a therapy that still arouses such passionate controversy after 60 years that supporters and opponents cannot even agree on its name.

Proponents call it electroconvulsive therapy, or ECT. They say it is an unfairly maligned, poorly understood and remarkably effective treatment for intractable depression.

Critics call it by its old name: electroshock. They claim that it temporarily "lifts" depression by causing transient personality changes similar to those seen in head injury patients: euphoria, confusion and memory loss.

Both camps agree that ECT, which is administered annually to an estimated 100,000 Americans, most of them women, is a simple procedure -- so simple that an ad for the most widely used shock machine tells doctors they need only set a dial to a patient's age e and press a button.

Electrodes connected to an ECT machine, which resembles a stereo receiver, are attached to the scalp of a patient who has received general anesthesia and a muscle relaxant. With the flip of a switch the machine delivers enough electricity to power a light bulb for a fraction of a second. The current causes a brief convulsion, reflected in the involuntary twitching of the patient's toe. A few minutes later the patient wakes up severely confused and without any memory of events surrounding the treatment, which is typically repeated three times a week for about a month.

No one knows how or why ECT works, or what the convulsion, similar to a grand mal epileptic seizure, does to the brain. But many psychiatrists and some patients who have undergone ECT say it succeeds when all else -- drugs, psychotherapy, hospitalization -- have failed. The American Psychiatric Association (APA) says that about 80 percent of patients who undergo ECT show substantial improvement. By contrast antidepressant drugs, the cornerstone of treatment for depression, are effective for 60 to 70 percent of patients.

"ECT is one of God's gifts to mankind," said Max Fink, a professor of psychiatry at the State University of New York at Stony Brook. "There is nothing like it, nothing equal to it in efficacy or safety in all of psychiatry," declared Fink, who is so committed to the treatment that he remembers the precise date in 1952 that he first administered it.

There is no doubt that mainstream medicine is solidly behind ECT. The National Institutes of Health has endorsed it and for years has funded research into the treatment. The National Alliance for the Mentally Ill, an influential lobbying group composed of relatives of people with chronic mental illness, supports the use of ECT as does the National Depressive and Manic Depressive Association, an organization composed of psychiatric patients. The APA, the Washington-based trade association that represents t he nation's psychiatrists, has long battled efforts by lawmakers to regulate or restrict shock therapy and in recent years has sought to make ECT a first-line therapy for depression and other mental illnesses, rather than the treatment of last resort.

And the Food and Drug Administration has proposed relaxing restrictions on the use of ECT machines, even though the devices have never undergone the rigorous safety testing that has been required of medical devices for the past two decades. (Because the machines had been used for years before the passage of the 1976 Medical Device Act, they were grandfathered in with the understanding that they would someday undergo testing for safety and effectiveness.)

Many of the nation's most prestigious teaching hospitals -- Massachusetts General in Boston, the Mayo Clinic, the University of Iowa, New York's Columbia Presbyterian, Duke University Medical Center, Chicago's Rush-Presbyterian-St. Luke's -- regularly administer ECT. In the past three years a few of these institutions have begun to use the treatment on children, some as young as 8.

Managed care organizations, which have sharply cut back on reimbursement for psychiatric treatment, apparently look with favor upon ECT, even though it is performed in a hospital and typically requires the presence of two physicians -- a psychiatrist and an anesthesiologist -- and, sometimes, a cardiologist as well. The cost per treatment ranges from $300 to more than $1,000 and takes about 15 minutes.

Medicare, the federal government's insurance program for the elderly, which has become the single biggest source of reimbursement for ECT, pays psychiatrists more to do ECT than to perform medication checks or psychotherapy. Increasingly, the treatment is being administered on an outpatient basis.

In the Washington area more than a dozen hospitals perform ECT, according to Frank Moscarillo, executive director of the Washington Society for ECT and chief of the ECT service at Sibley Hospital, a private hospital in Northwest Washington. Moscarillo said that Sibley administers about 1,000 ECT treatments annually, more than all other local hospitals combined.

"With the insurance companies there isn't a limit [for ECT] like there is for psychotherapy," said Gary Litovitz, medical director of Dominion Hospital, a private 100-bed psychiatric facility in Falls Church. "That's because it's a concrete treatment they can get their hands around. We have not run into a situation where a managed care company cut us off prematurely."