I'm not sure if I'm supposed to admit it as a psychiatrist in training, but electroconvulsive therapy -- shock treatments -- makes me nervous.

Like a lot of people, I remember vivid images of the practice from the movie "One Flew Over The Cuckoo's Nest," but those aren't what I find discomforting. Advances in electroconvulsive therapy (ECT) have made the procedure more routine than startling. ECT has been proven to be remarkably effective against depression. I think I'm nervous because passing a small amount of electrical current through the brain does help alleviate some serious cases of depression, but for reasons no one can explain.

Not knowing how ECT works is hard for me to tolerate; as someone who has spent 11 years immersed in the study of science and medicine, I want to know precisely which gears of illness I interfere with. Strange that I worry little about the brain chemicals I set in motion with psychotherapy. I'm comfortable with intuition and insight. I'm a mind doctor. But when I use a machine and resort to electricity, I feel like a brain doctor. I wear my white coat. I drape a stethoscope around my neck.

The room is quiet. We talk softly. There is a box that looks like a small generator, maybe a foot square, with buttons and dials on it, a few wires protruding. A specialist administers general anesthesia, as well as a medicine that temporarily paralyzes all of the patient's muscles. This prevents the violent convulsions that used to be caused by more primitive forms of shock treatment.

In order to know that modern ECT is working at all, we inflate a blood pressure cuff on one arm. That stops the paralyzing medicine from circulating to it, and that arm is the only part of the body that moves during the seizure. We need to see something move, because the seizure tells us that the ECT is causing a major electrical disturbance in the brain, and longer seizures mean a more effective treatment.

The electrodes are half-dollar-sized metal plates covered with conductive gel. Typically, one is held firmly to the patient's temple and another to the top of his or her head. With the patient asleep, a button is pressed to deliver a two-second dose of electricity. There is no frightening noise, no wild jerking, no pain. Attention focuses on that one arm as it bends stiffly at the elbow and shakes. We clock the time, ideally 30 to 60 seconds, until it relaxes. It may be only minutes before the patient leaves the room, awake and moving.

That, anticlimactic as it may sound, is high drama for psychiatrists. Many of us don't think of ourselves as doing things to patients. Not in the way a surgeon thinks of cutting out a clogged length of artery. We are trained in diligence and patience. We accept that the fruits of our labor may be a delicate change in perspective or rise in self-esteem. Even when we use medicines, we know that improvement may take weeks or months. We learn to accept subtle recoveries. A seizure as evidence of our intervention stands in sharp contrast to our usual slow and cautious approach.

The fact is that ECT works better than counseling or medication for some patients. Some studies have shown that as many as 90 percent of drug-resistant depressed patients improved, generally with six to 12 treatments. Because depression is often an episodic illness and the effect of ECT doesn't last forever, it may need to be repeated.

There are theories about why ECT works. Causing a major electrical disturbance in the brain may help fight depression by exhausting more random, abnormal discharges. Or it may work because it increases or diminishes the sensitivity of various chemical receptors in the brain. These receptors receive messages via the same chemical messengers in the brain that are disordered in people who are suffering from depression.

Why, if ECT is so effective, do we use it so infrequently? One reason is that the procedure carries the complications and risks of general anesthesia, with approximately one death in every 25,000 cases. Another is that ECT can cause loss of memory, particularly of events that occur just prior to treatment. Although the amnesia is usually mild and, in fact, undetectable after several months, some patients complain of lasting memory problems.

Medicines, of course, have their own side effects. And, sometimes, these are more alarming than the ones associated with ECT. The real reasons have more to do with fear than facts. ECT has a bad reputation, a legacy of the decades when it was used indiscriminately without anesthesia and towels were stuffed in the mouths of patients to prevent them from biting off their tongues. In those circumstances, bones sometimes fractured from the force of muscle contractions.

Hollywood, as in "Cuckoo's Nest," did its part by portraying ECT as a way of punishing free thinkers and controlling their minds. It is no surprise that, to this day, those who benefit from the treatment are reluctant to support it publicly, lest they be branded defective or incompetent.

Unlike medications, ECT is not profitable to industry. If it were, there might be a flurry of industry-supported research to document its effectiveness and reduce its stigma. Psychiatrists would get the same hard-sell educational materials on ECT as we do on antidepressants. Maybe even some pens, pads of paper and briefcases with little lightning bolts or something, just like the ones we get with drug logos. But it's the power company that is paid for electrical current, not a pharmaceutical manufacturer.

Doctors make decisions in a complex social context. We incorporate in our treatments the acceptability -- to ourselves, the patient, the public and the profession -- of the therapeutic strategies we employ. And the fact is that psychiatrists remain more reluctant to perform ECT than to use many medications that can have more lasting side effects.

So it may be that, even when ECT would be the most effective treatment for a patient, it won't be prescribed. Not because it won't work, but because it won't be well-received.

Keith Russell Ablow is a resident in psychiatry at New England Medical Center in Boston.