She's 68, but she looks younger. Her eyes sparkle with childlike curiosity and her voice is a honeyed, sassy whisper. Southern through and through, that's Madeline LaDrue - although that's not her real name. She wants to remain anonymous, even though a few of her friends know.

They know that Madeline's depression is being treated with electroconvulsive therapy at St. Joseph's Hospital in Tampa. Once every six weeks, since March. And that it "gave me my life back,'' Madeline says cheerily. "If people think it's barbaric today, well, they're ignorant.''

Electroconvulsive therapy - which practitioners prefer to the term shock therapy - means many things to many people. Proponents say that it is enormously effective in the short run and that it may be far safer than antidepressant drugs. Opponents argue it damages the brain and that the temporary relief of depression is no substitute for some patients' profound and permanent memory loss.

Either way, electroconvulsive therapy has returned to mainstream medicine. In the Tampa Bay area, a handful of hospital-based psychiatrists perform the procedure on their most severely depressed patients, many of them older, most suicidal and psychotic. All are clearly unresponsive to medication. The typical course is a series of six to 12 treatments over a period of a few weeks. Then the therapy is reduced to one treatment a month or less, depending on the patient's relapse rate.

Memory loss and confusion are common side effects of shock therapy, and doctors admit there is no way to predict the severity of a patient's loss. It ranges from slight, forgetting only those events just before and after treatment, to severe, forgetting incidents and information acquired months or years before.

Nonetheless, "it's the best thing that ever happened to me,'' says Madeline, as she lies on a bed minutes before her treatment. James Adams, medical director of psychiatric services at St. Joseph's Hospital, and Malcolm Klein, an anesthesiologist, are at her side. So are several nurses.

They will monitor her blood pressure, her respiratory rate, her heart rate and blood oxygen level throughout the procedure. They will also administer a muscle relaxer and a very short-acting anesthetic; for three to five minutes, a machine will do the breathing for her.

But it is the electrodes on Madeline's temples that are at the center of all this attention. With a nod from James, a box the size of a stereo receiver delivers a pulsing, electrical charge about one-fourth the power of that used to revive a heart by electrical stimulus. The charge surges through her brain, inducing a seizure or convulsion. For 57 seconds. That goes virtually undetected by observers except for the slight strain of a muscle in her neck - and a paper strip from the electroconvulsive therapy machine. It spits out a jagged squiggle, similar to seismograph recordings of an earthquake.

Within five minutes, Madeline is awake and answering questions. And smiling at the people around her.

"I think of it as ECT of the heart and ... nobody thinks anything about starting the heart with an electrical shock after heart surgery,'' says Klein, who has worked with shock therapy patients since 1992.

Adams, who has administered the therapy since 1990, is likewise pragmatic. He considers it a treatment of last resort, only for the severely ill, despite the remarkable success he has seen in his psychiatric practice. Up to 95 percent of his patients felt their depression subside after the therapy.

Yet science continues to wrestle with precisely why it works, and how. And the public continues to perceive the procedure as a harrowing, horrible form of torture, like that depicted in the movie, "One Flew Over the Cuckoo's Nest.''

Electroconvulsive therapy was introduced in 1938 by an Italian scientist who tried it on several patients. It apparently relieved their depression and quickly became something of a psychiatric fad, applied to the mentally ill with little regard for accurate diagnosis or side effects.

By the late 1960s, the therapy had fallen out of favor. Only in the last 10 to 15 years has it become more acceptable, as researchers have modified the electrical charge and minimized the patient's discomfort. Nowadays, for example, patients get a muscle relaxer. For years they didn't, and fractured bones often followed the induced seizure.

The technique may be modified in some patients, since an electrical charge can dramatically alter blood pressure or heart beat. Nevertheless, many practitioners feel it is less risky than drugs, particularly in patients whose conditions are complicated by antidepressants: pregnant women, the elderly, the seriously physically ill.

Harold Sackeim, chief of the department of biological psychiatry at New York State Psychiatric Institute and one of the country's leading electroconvulsive therapy researchers, theorizes that the brain of a depressed person is actually working too hard and too long, like an engine that idles too fast. The therapy slows the idle. As strange as it sounds, Sackeim says, research on individuals who are catatonic - who don't respond to their environment - show that their brains are "literally buzzing away.''

"I have patients who have appeared on Broadway the night of their ECT,'' Sackeim says.

In England and Sweden, electroconvulsive therapy is a first-line treatment. If you are hospitalized for depression, shock therapy is among your first choices, not your last, Sackeim says. In the United States, the therapy is far less common. About 50,000 patients a year receive the therapy and, without insurance coverage, it costs about $500 a treatment.

It also requires the patient's signature on a lengthy legal document. "To my understanding, it is the most detailed consent form in medicine,'' Sackeim says.

In fact, American Psychiatric Association guidelines for electroconvulsive therapy, issued in 1990, fill more than 200 pages. And at St. Joseph's Hospital, no patient can receive it unless they first view a videotape of the procedure and sign a complex consent form. Furthermore, Adams says, a patient who is ruled incompetent cannot receive the therapy unless a motion requesting the procedure is filed in court.