Mrs. Smith was having a rough time. At age 70 her mood swings were becoming more frequent and more extreme. Then she became locked in a deep depression. Unable to sleep and losing weight, Mrs. Smith had no interest in doing things and had trouble concentrating. She voiced ideas that she was a worthless person, that she would be imprisoned for some heinous crime she must have committed, that she wanted to die. Even the support and reassurance of her loving husband of 49 years had no effect.

Many older individuals who display difficulty caring for themselves or thinking clearly are assumed to be hopelessly "senile" and put into nursing homes. Mrs. Smith, however, was suffering from an illness, manic-depression. The medications that had been helpful in maintaining a level mood were no longer working. Electroconvulsive therapy was recommended.

The convulsive therapies were developed half a century ago in the belief that epilepsy and the severe mental illness schizophrenia could not coexist in the same person. Although that theory has not held up, the therapy itself has stood the test of time for one reason: It works.

Not on everyone, to be sure, and not even on many of the schizophrenic patients it was originally designed to help. But for many people with severe depressive illness, convulsive therapy is the best, fastest or at times the only treatment available even today. For a person with a mood disorder to the point of not moving, eating or drinking, convulsive therapy can be lifesaving.

Electricity did not become part of the treatment until several years after its development. It replaced the convulsant drugs originally used to induce therapeutic seizures because it was safer, able to be more precisely calibrated and therefore more predictable. Patients today don't feel an "electric shock" during electroconvulsive therapy (ECT) because they are fast asleep during treatment. The production of seizure activity in the brain -- not in the body, which is protected by muscle relaxant drugs -- seems to be the necessary therapeutic ingredient of ECT. There are many theories of how ECT does or does not work. There are, however, fewer facts.

As the option of ECT was discussed with Mrs. Smith (not her real name, but an actual person) and her family, they were told of the potential drawbacks as well as advantages of the treatment. There are conceivable adverse effects of general anesthesia. As with some surgical procedures, ECT was overused in the past. ECT is not appropriate for everyone who feels depressed.

Modern methods of psychiatric diagnosis enable a distinction to be made between patients suffering from the illness of melancholia and those who are merely unhappy with their lives; only the former group requires biological treatment of depression.

The potential problem worrying Mrs. Smith's physicians was memory disturbances. ECT can induce temporary confusion and memory loss, which does not mean that brain damage has occurred but may reflect temporary impairment of function. Most patients forget things that happened around the time (generally three or four weeks) treatment is given. But six months after the end of treatment it is difficult to demonstrate memory deficits or other signs of brain damage in nearly all people. There are some people who firmly believe that they have experienced permanent memory loss, but it is impossible to assess these statements objectively.

In recent years there have been two major advances in ECT administration that can reduce confusion or memory problem. Over the past decade the nature of the electrical stimulus in state-of-the-art ECT machines has been refined: Instead of a relatively long, slow current wave, the new apparatus gives a series of brief mini-pulses of current that total a fraction of that of earlier models. The location of the two electrodes on the scalp also makes a difference. Standard procedure calls for placement of one electrode on each side of the head, so-called bilateral ECT. Numerous studies have demonstrated a reduction in confusion and memory loss when both electrodes are put on the same side, generally the right, in "unilateral" ECT.

Even under the best of circumstances ECT is not risk-free, the Smiths were advised. They signed an informed consent document complete to the point of citing death as an outcome in one of every 20,000 people treated. To place this in proper context, suicide claims the lives of 15 out of every 100 victims of major depression.

The Smith family was also told that if there were a way to induce the therapeutic effects of ECT without the possible complications, without the anesthesia, without the electricity, and even without the convulsion, a major advance in the struggle against depression would be achieved. To that end Mrs. Smith was asked, and agreed, to participate in research designed to understand better what and how ECT was doing. Only in this way can the treatment be made safer, more effective and, hopefully, unnecessary.

On June 10 to 12 the National Institute of Mental Health will hold a consensus development conference in Bethesda on the subject of ECT. The goal will be to separate fact from opinion, to clearly state what is known at present and what needs to be known to usher in a new genertion of powerful antidepressant treatments.

Mrs. Smith is back home now. She was confused for about 30 minutes after each of her ECT treatments but soon recognized the familiar reassuring faces around her. A week after leaving the hospital in remission from her depression, Mrs. Smith and her husband traveled to the Midwest. They celebrated their golden anniversary in the church where they were married 50 years ago.

"I remember it well," she said.