Mario Della Grotta lay awake on the operating table as doctors drilled two half-inch holes in his skull. He could hear the drill’s whine, feel its vibrations in the bone. But he sensed nothing when they took the crucial step: sliding a pair of wires deep into the white folds of his brain.

It was February 2001, and Della Grotta, then 32, was the first person in the United States to undergo this procedure, which took place at Rhode Island Hospital. He had waited eagerly for a year — even though he didn’t know whether the surgery would help him or kill him.

The wires in his brain had slender electrodes at their tips, and Della Grotta hoped their pulsing would quiet the ceaseless demands of obsessive-compulsive disorder, a form of anxiety that induces a need to check, order, clean and repeat beyond all reason.

OCD had held him prisoner for two decades, requiring him to keep his books alphabetized, his closet organized by color and size, his groceries stacked neatly in the cart, his handwriting free of cross-outs. It made him wash his hands till they were raw, and iron even his socks.

Worse, OCD commandeered his mind, filling it with unwanted thoughts. Della Grotta would awaken before dawn each day and lie immobile for hours, planning his every move. Numbers — 17, say, and then, 64 — would pop into his head, and he would have to multiply them. Once he used up five hours recollecting how he’d spent every penny of a $5 bill.

The National Institute of Mental Health estimates that 2.2 million American adults have obsessive-compulsive disorder. Chances are good that everyone knows someone who suffers from it. Celebrities who have spoken about having OCD include comedian Howie Mandel, radio host Howard Stern and actor Alec Baldwin. Charles Dickens, Charles Darwin, Florence Nightingale and, as famously portrayed in the movie The Aviator, billionaire Howard Hughes are all said to have suffered from it.

Many people with OCD lead productive, meaningful lives, managing or hiding their symptoms. Probably four out of five of those who get the appropriate treatments — medications and a specialized form of behavioral therapy — can bring their symptoms under control.

But not Mario Della Grotta. His OCD started when he was 10 and got worse and worse. He tried everything, and nothing worked. By the time he was 30, obsessions and rituals were occupying his every waking hour, impervious to medications, too intense for therapy. He could not finish college. He could not hold down a job.

One day Della Grotta stood on the top level of the Providence Place mall and looked over the balcony to the floor more than 40 feet below. He thought: If I jump, I won’t have OCD anymore.

For someone who had reached that point, experimental brain surgery wasn’t such a big leap.

NO ONE invited the media to the pioneering operation on Mario Della Grotta. Not one press release trumpeted the occasion. Quite the opposite: For Rhode Island Hospital neurosurgeon Gerhard M. Friehs and Butler Hospital psychiatrists Benjamin D. Greenberg and Steven A. Rasmussen, publicity was the last thing they wanted.

These researchers, all connected with Brown Medical School, knew how it might look to outsiders, this business of trying to change a man’s behavior by tampering with his very brain. Hanging over them was the grim history of “psychosurgery,” performed during the 20th century without ethical guidelines, informed consent or even evidence that it did more good than harm. Thousands of people — including prisoners and children, people who were mentally ill or merely troublesome — underwent lobotomies with an ice pick inserted through the eye socket into the brain. Would the work at Brown be viewed as, in the words of one critic, “an electrical prefrontal lobotomy”?

But to the Butler Hospital psychiatrists, equally as worrisome as those who would condemn the surgery were those who would yearn for it. The doctors didn’t know whether the procedure, called deep brain stimulation, would ease OCD — but they did know the suffering that OCD causes, and the desperation of its sickest victims. They didn’t want patients flocking to them — or, worse, to less experienced doctors — looking for quick brain repair.

This was an experiment, not a cure.

But it was, no question, an attempt to fix the brain. OCD is thought to spring from a malfunction in neurological circuitry that can be seen on MRI images: when a person with OCD engages in obsessive thoughts, certain areas of the brain light up more than they would in a normal person, a sign of heightened activity.

The disorder may be an exaggeration of normal behaviors that enhance survival, behaviors that evolution hard-wired into the human brain — watching for predators, checking to make sure the fire is out, protecting children, avoiding disease.

But with OCD something goes awry in the brain pathways that control these functions. The alarm signals of fear (“Make sure the door is locked!”) can’t be quieted by assurances from the rational brain (“I checked. The door is locked.”). So the OCD sufferer, even though he knows he locked the door, still feels that something is wrong, that he must keep checking.

MARIO DELLA GROTTA first contacted me in 2003, eager to tell his story. He had a mission: to help people understand OCD and recognize it as a genuine disability. I kept in touch with him over the years, through the ups and downs of his illness.

Despite his anxieties, during our conversations Della Grotta never appeared nervous or fussy. He came off as affable, even placid. Tall and stocky, he usually sports a crew cut that reveals the two bumps near the top of his head. This is where the wires emerge and coil inside a plastic cap beneath the skin. Invisible, they snake under the skin behind his ears and down his neck to the batteries implanted in his chest.

Della Grotta grew up in the Silver Lake section of Providence, and also in Johnston, the third of four children of a homemaker and a businessman, who died when he was 14. His mother, Madonna, remembers Mario as a good kid, easy to care for as a baby, an average student. It’s true that he was always neat and clean, and didn’t like getting his hands dirty, but that wasn’t much different from some of his cousins’ behavior. Or from that of his mother, who used to spend several hours a day cleaning the house.

A propensity for OCD can be inherited, but it’s not clear whether parenting or childhood experiences have any role in bringing it on. Does a rigid or compulsive parent foster OCD in the child, or do both parent and child share an inherited illness? Madonna Della Grotta now thinks that she and some of her relatives may have had symptoms of OCD, but until Mario was diagnosed she had never heard of it. She remembers that Mario had an uncle who would wipe the silverware at weddings before eating, but people just thought he was quirky.

Mario thinks his symptoms started when he was in fifth grade. He remembers counting in his head all the time, and repeatedly writing the letters of his name with his finger on his pants.

As a teenager he worked as a busboy at a Federal Hill restaurant. Hundreds of times throughout the day, he would mentally review his uniform for that night: “I have my socks, shoes, pants, underwear, bow tie.” When he got to the restaurant, he would mentally repeat it in reverse. He couldn’t stop it, and he couldn’t understand it. “I would have these thoughts: ‘Am I going crazy? Why am I repeating? Why am I counting?’ At one point I literally thought I was going crazy. I didn’t know what was happening to me.”

When he was in his mid-20s, Della Grotta got a job as a bookkeeper for the Roman Catholic Diocese of Providence. Now that he was responsible for counting money, his illness exploded. He would spend all day, into the evening, checking the budget line by line, torn by fear that he might have missed something.

Despite his fixation on money, Della Grotta developed a new fear: pennies — he couldn’t bear to hold them because of the copper smell.

The objects, thoughts or situations that torment people with OCD vary greatly, ranging from the routine to the bizarre. The common theme is an irrational fear that sparks a compulsive action or ritual intended to calm the fear.

A person might fear that his family will be harmed, but feel somehow that counting to five before crossing the threshold will keep them safe. Another worries that she left the coffee machine on, even though she can remember turning it off. She goes back home again and again to check on it.

“Imagine you were shopping in the supermarket with your 2-year-old son,” says D. Matthew Evans, a psychologist who specializes in treating OCD, “and you looked down and found he was gone.” The blinding terror you would feel, the urgent need to act, is similar to what a person with OCD experiences when faced with what he or she fears. “It really grabs people, commands their attention,” Evans says.

Checking and rituals bring temporary relief but feed the illness, giving it strength to demand more. The counting that occurred at the front threshold may soon be necessary at every doorway. The person worried about the coffee machine may end up leaving work in the middle of the day to check on it, or even bringing the machine to the office with her. Most sufferers know their behaviors make no sense, but still they can’t stop.

In the years after high school, Mario Della Grotta lived with his illness without understanding or even acknowledging it. But good things were happening in his life as well. He started dating Sheri Richardson, a friend of his sister’s who’d had a crush on him all through high school and finally caught his eye after they graduated. Sheri was in college; Mario was working and taking courses.

While they were dating, Sheri noticed Mario’s need to check things and account for things, and his fixation on money.

Not until after they married, though, in 1995, did she suspect that something was seriously wrong. Mario counted everything — his books, his ties, his pants. When Sheri spent money, he demanded to know where every penny had gone. He insisted that she organize the cards in her wallet alphabetically.

“We used to get into arguments,” Sheri recalls. “I would get really frustrated with it and really upset. I felt like I was walking on eggshells: ‘What’s going to trigger him next? He just keeps on and keeps on and keeps on.’ ”

One day, Mario discovered a messy drawer in the kitchen. He took out all the stuff and started showing Sheri how to organize it. “Everyone has a junk drawer,” she declared, and threw everything back into the drawer in a heap. Mario flew into a panic. “What are you doing, Sheri!” he remembers crying.

SHERI WORKED as a research assistant at Butler Hospital, a psychiatric hospital in Providence; she knew something about mental illness. She kept telling Mario that she thought he had OCD and eventually connected him with Dr. Jane L. Eisen, one of Butler’s OCD experts. Eisen started Mario on medication and referred him to Matt Evans, the psychologist who specializes in behavioral therapy for OCD.

The medication had no effect. The therapy was unbearable.

Evans employs a form of cognitive-behavioral therapy that is considered the gold standard for treating OCD — exposure and response-prevention treatment. The patient confronts the source of anxiety and tries to resist the urge to respond with a compulsive act or ritual. A person who worries whether his door is locked will sit still, withstand the anguish, and avoid checking the lock. Evans urged Della Grotta to put his hand in the wastebasket, and restrain himself from washing. But Della Grotta couldn’t hold still long enough.

To succeed, people need to tolerate the exposure for a long time, typically 30 minutes, and they need to repeat the exercise again and again. With perseverance, the patient’s fear dies down — because, as Evans puts it, “the body becomes bored with what was once very scary.” These changes often last longer than those brought about by medication. In fact, imaging studies have shown that behavioral therapy rewires the brain, quieting the hyperactive circuits implicated in OCD.

But OCD is an illness always lying in wait, ready to spring back. “Think of it as this live entity, this animal,” Evans says.

In Della Grotta’s case, the animal had its claws deeply embedded. “The more we got to know Mario,” says Evans, “the more we saw how disabled he was. He was as sick as anyone we’ve seen here.”

Eisen, Della Grotta’s psychiatrist, put him on one medication after another. None had any noticeable effect on his OCD symptoms. Della Grotta enrolled in an intensive inpatient program in Massachusetts. Trying to build tolerance for the things he feared, the staff toppled the groceries in his cart, tangled the clothes in his drawer, and turned off the shower while he still had shampoo in his hair. Della Grotta couldn’t take it, and went home after five days, more discouraged than ever.

That’s when Jane Eisen sent him to meet Steve Rasmussen.

RASMUSSEN IS the boyish-looking medical director of Butler Hospital, a psychiatrist specializing in anxiety disorders who has in recent years focused on OCD. He has an easygoing, offhand manner that probably soothes his anxiety-stricken patients — but belies the radical work he’s been doing.

Since 1993, with little notice from the outside world, Rasmussen has been overseeing a most unusual treatment for severe OCD: burning tiny lesions on the brain.

This is accomplished with a radiological device at Rhode Island Hospital called the Gamma Knife, which emits highly focused beams of gamma radiation. Operated by Dr. Georg Noren, the Gamma Knife enables doctors to work on the brain without opening the skull, and to target narrow areas without affecting surrounding tissue. It’s used chiefly to eradicate brain tumors or correct malformed blood vessels.

When Rhode Island Hospital acquired the Gamma Knife, in 1992, Rasmussen saw an opportunity. He wanted to take advantage of the growing knowledge of the brain’s anatomy and the improving ability, through new imaging techniques, to pinpoint brain structures. He knew, reasonably well, which of the brain’s crevices harbor OCD.

The first patient in the Gamma Knife experiment was a 20-year-old from Nebraska who was so stricken with OCD that he could scarcely speak or eat. Each movement he wanted to make was preceded by so many rituals he was essentially paralyzed. It would take 10 minutes to put a grain of rice on his fork, another 10 minutes to bring the fork to his mouth. His parents would wake him at 4 a.m. to pour a nutritional drink down his throat.

Since then, the Gamma Knife procedure has been done on 52 people. Seventy percent of them have seen significant improvement, Rasmussen says. Only one suffered a serious side effect — apathy and a lack of engagement with her family — but that improved after several years.

As for the young man who couldn’t eat: he’s now in his fourth year of medical school.

Then, in the late ’90s, Rasmussen started hearing about a new treatment for Parkinson’s disease.

Doctors were implanting electrodes deep in the brain center that controls movement. The electrodes emitted a frequency that stopped the tremors that disable many Parkinson’s patients. The procedure, known as deep brain stimulation, won approval from the U.S. Food and Drug Administration in 1997 as a treatment for tremors.

That year, Dr. Gerhard Friehs started performing deep brain stimulation at Rhode Island Hospital in people with Parkinson’s disease.

Rasmussen immediately saw the potential for treatment of OCD. If the electrodes were placed near where he’d been burning the lesion with the Gamma Knife, perhaps deep brain stimulation could also control OCD. Although such a procedure would require breaching the skull, it would offer an advantage: unlike a lesion, which can’t be changed, electrodes can be moved, turned on and off, and adjusted to different frequencies.

Rasmussen wasn’t the only one who had thought of this. In 1997, Dr. Bart Nuttin, in Belgium, performed the first deep brain stimulation on a patient with OCD. Rasmussen and colleagues flew to Belgium to observe the second such operation. Nuttin reported that his patients showed improvement.

BY THE TIME Mario Della Grotta came to Rasmussen in 2000, the psychiatrist was already preparing to study deep brain stimulation as a treatment for OCD, along with doctors at two other medical centers — the Cleveland Clinic and the University of Florida at Gainesville.

Della Grotta appeared to meet the study’s requirements — that the patient have suffered with severe OCD for at least five years, and have failed every other treatment, including behavioral therapy. Rasmussen estimates that no more than 5 percent of OCD patients meet those criteria.

At the time, deep brain stimulation had been tried on only five people with OCD — all in Belgium. The surgery, by opening the skull, would put Della Grotta at risk of infection, seizures or hemorrhage. It would involve implanting electrodes in his brain, perhaps touching his very mind. Plus, no one knew whether it would work.

Della Grotta did not cringe. In fact, he was thrilled. Rasmussen was offering him something new when all the old approaches had failed. Rasmussen sent Della Grotta across the Butler Hospital waiting room to his colleague, Dr. Benjamin Greenberg, leader of the deep-brain study.

Rasmussen had recruited Greenberg from the National Institute of Mental Health, where he had been head of adult OCD research. Greenberg holds a Ph.D. in neuroscience as well as a medical degree in psychiatry. A mentor had sparked his interest in OCD, and he stayed with it because he liked the patients so much. People with OCD, he says, are typically smarter than average, clear-eyed about their affliction and able to work on getting better.

When Greenberg met Della Grotta, he was impressed with the young man’s intelligence, the intensity of his suffering, and the supportiveness of his wife. But Greenberg’s first prescription was not surgery. He looked over the record and found that there was one medication Della Grotta had not yet tried, and he would not qualify for the deep brain stimulation study unless every standard therapy had failed. Greenberg told Della Grotta that maybe in a year the experiment would begin. Della Grotta, upset, told Greenberg he didn’t know if he could last that long.

It’s a slow process, getting such a project off the ground. Friehs, the neurosurgeon, says the notorious history of lobotomies weighed heavily on the researchers. Lobotomies had brought relief to some people suffering from agitation, anxiety and depression, but in some it also deadened emotions and personality, or caused disabling brain injury.

The shadow of those surgeries, Friehs says, “makes us very careful.”

The researchers took pains not to repeat the errors of the past — especially with respect to patient consent. In addition to winning approval from the boards that oversee human research at Rhode Island Hospital and Butler Hospital, and obtaining special permission from the U.S. Food and Drug Administration to use the implant experimentally, the researchers created a separate ethics panel. Made up of a clergyman, a psychiatrist and a mental-health advocate, the panel would ensure that the patients who entered the study understood the risks and expected no sure benefit, although they could always hope.

For Della Grotta, it was a long hellish year. The last-ditch medication that Greenberg prescribed wasn’t working — no surprise there. Della Grotta’s sickness was so confining that sometimes he longed to die.

His wife remained steadfast, even amid the loneliness. Sheri discovered that nobody, but nobody, understood what she and Mario were going through, no matter how well she explained it. Even people she thought were smart, people she thought were her friends, raised voices in judgment rather than sympathy.

“What do you mean, ‘he counts’? Why does that keep him from working?” she remembers one person saying.

Sheri went to church every Sunday and every day prayed for help. She relied on her family, put her faith in the doctors, and hoped that someday Mario would get better.

In the midst of all this, Sheri learned that she was pregnant.

One day, a few months into her pregnancy, Sheri fell on ice on the front steps of their Cranston house. “I went back in to tell Mario. ‘I’m going to go to church. Then I’m going to the hospital to get checked. Come with me to the hospital.’ ”

Mario was in bed, paralyzed by his obsessive thoughts, his need to plan and calculate. “He couldn’t even bring himself to get out of bed and go to the hospital,” Sheri says. “It’s like you have a third person in your marriage who occupies your husband.”

Sheri didn’t share Mario’s enthusiasm for surgery. She found it too radical — terrifying, actually. But Mario was determined.

Finally, a date was set for his surgery. The baby was due the following month. Della Grotta knew that one risk of any brain surgery is death. (About one-half of one percent of Parkinson’s patients who receive deep brain stimulation die from surgical complications, according to Friehs.) Della Grotta got a tattoo on the top of his right wrist, the Chinese character meaning “child.” If he died, he wanted to go to his grave with some memento of his unborn daughter.

FEB. 5, 2001: Mario Della Grotta arrived early at Rhode Island Hospital.

He received a sedative to ease the ordeal, but he had to be conscious for the surgery so doctors could monitor his responses. As participants later described the operation, the neurosurgeon first encased Della Grotta’s head in a device called a stereotactic frame — a band of metal attached at ear level, with pegs screwed into skin and bone, and a semicircular arc over the top of his head. Then Della Grotta was wheeled into the MRI room for pictures that would locate the relevant brain structures and measure their distance from the metal arc.

Next, Della Grotta went to the operating room.

This is who was there: Greenberg, Della Grotta’s psychiatrist and the leader the experiment; Rasmussen, medical director of Butler Hospital and also a key researcher; Friehs, the neurosurgeon; the surgical resident working with Friehs; the anesthesiologist and nurse anesthetist; two or three nurses; two representatives of the device manufacturer, Medtronic, which was donating the electrodes and related devices; and Nuttin, the Belgian surgeon who had first tried deep brain stimulation to treat OCD.

On the operating table, Della Grotta asked Greenberg, “Is everything going to be okay?” Greenberg assured him that he would be fine, reminding him that his wife was waiting for him and that his first child would soon be born.

A numbing agent was injected into the scalp. Friehs turned on a drill with a half-inch bit, which whirred as it penetrated the skull. Next Friehs sliced an x-shaped slit in the tough membrane that covers the brain, as he described the procedure later. Then he threaded a slender, hollow spike through a clamp on the arc over Della Grotta’s head. It gently pushed aside brain tissue without cutting it.

The brain feels no pain, so Della Grotta didn’t flinch as the guide tunneled into the junction of two structures called the internal capsule and the ventral striatum. Neural signals whizzing through this spot, up to 50 times a second, connect the thalamus, which regulates alertness, mood, sensation and actions, with the orbitofrontal cortex, which assesses rewards and punishments. OCD is thought to arise from rogue signals traveling that circuit.

The goal here was to interrupt the faulty signals, to jam them with a manmade buzz.

Through the center of the spike, Friehs inserted the wire with the slender electrode at its tip. He removed the guide and left the electrode in place. Then Friehs repeated this process on the other side.

When both electrodes were in place, they were attached by a temporary extension wire to the external stimulator, a box the size of a cigarette pack, operated by Greenberg.

Greenberg turned it on, and an electrical current flowed into Della Grotta’s brain.

As Greenberg recalled it later, Della Grotta’s mood instantly brightened. He became more alert, more talkative. Greenberg handed Della Grotta some pennies, objects that had previously filled him with horror because he hated that copper smell.

Della Grotta held the pennies calmly, tossed them from one hand to the other. Greenberg turned off the power to the electrode and suddenly the pennies were again unbearable — Della Grotta dropped them.

Friehs says that even though deep brain stimulation has been used to treat tremors in some 30,000 people with Parkinson’s disease, no one knows exactly how it works. It might put cells to sleep, preventing them from firing signals. Or it might synchronize cells that were firing chaotically.

For about an hour in the operating room, Greenberg tested the system, looking for effects and side effects as he tried different frequencies and different contacts on the electrodes. Then he turned off the system, and Della Grotta went under general anesthesia so that two stimulators — slender battery packs the size of a pager — could be installed under the skin of his chest. They would power the electrodes, and also allow doctors to adjust their frequency.

After a couple of days in the hospital, Mario Della Grotta went home to recover, with the batteries off.

THREE WEEKS later, Della Grotta reported to Greenberg’s office at Butler Hospital. The psychiatrist opened a briefcase containing computer equipment. Attached by a coiled wire was a device like a large computer mouse. He pressed it against each of the batteries in Della Grotta’s chest. Via radio waves, the device communicated with the stimulators, and one by one, Greenberg turned them on.

Della Grotta looked cheerier. This, Greenberg says, was typical of OCD patients who got deep brain stimulation, most of whom also suffered from depression. “The first thing that seemed to change in OCD patients,” says Greenberg, “was their mood — their motivation, their ability to experience positive emotions. When stimulation stops, one of the first things that gets worse is depressive symptoms.” (The finding has led to experiments using deep brain stimulation to treat depression.)

Greenberg speculates that deep brain stimulation may work in part because it alleviates other problems that often surround OCD — depression, general anxiety, lack of motivation. Patients feel better, so they’re better able to tackle their symptoms.

Every day for two weeks, and several times for a couple of weeks afterward, Della Grotta went to Greenberg’s office. He stayed there for hours as Greenberg adjusted the frequency of the current from his stimulators. Sometimes he felt more anxious, sometimes less. Sometimes he felt a little tingling. Sometimes a wave of sadness would engulf his body.

One day in those early weeks, Della Grotta went home feeling especially good — chatty, engaged, joking. Soon, though, it became clear that he felt too good: he couldn’t sleep; his mind was racing. After four days, Mario and Sheri went back to Greenberg.

Greenberg opened the little briefcase and pressed the device against Della Grotta’s chest. He punched the buttons to lower the frequency.

Sheri watched in astonishment. The minute Greenberg turned down the stimulator, Mario’s face fell, overtaken by fatigue.

“Doctors can manipulate equipment in his body so his behavior changes,” Sheri said later, with something like awe, if not horror, in her voice. “You feel like a flip of a switch can change your behavior. . . . He referred to himself as feeling like a robot.”

WAS MARIO Della Grotta being manipulated by a machine? Was he losing himself to the electrodes’ control?

Friehs, the neurosurgeon, turns the question around: “How much of yourself are you when you have severe intractable OCD? Is this [illness] part of him, or something controlling him?

“We don’t change personality,” Friehs says. “Making a different person isn’t what we want. What we want is to help people be themselves again.”

Greenberg puts it this way: “Nothing is worse in terms of mind control than OCD. … We’re not substituting a personality. We’re unmasking who he is.”

But others find it simply scary.

Dr. Jeffrey M. Schwartz, a research psychiatrist at the University of California at Los Angeles, who wrote the book Brain Lock, a popular guide to overcoming OCD, calls deep brain stimulation “essentially nothing more than an electrical prefrontal lobotomy. It’s less crude than just sticking an ice pick in there.”

The label “deep brain stimulation,” in Schwartz’s view, is a marketing euphemism that makes an invasive surgical procedure sound like “a massage of your brain.”

“At Brown,” he says, “there are responsible people who are doing this. Greenberg is not a problem in and of himself. But there are very few people in the world who are as intelligent and careful as him. This thing has huge abuse potential.”

Schwartz faults the Brown researchers for plowing ahead with their work despite its hazards should it fall into less responsible hands. “They don’t want to think about what’s going to happen if they succeed,” he says.

And what will happen, in Schwartz’s view, is that private companies and doctors’ offices will offer deep brain stimulation to anyone who wishes to tune up his mental state. For example, says Schwartz, if the electrode were moved about one centimeter from the spot where it’s placed to treat OCD, it would land in the brain’s pleasure center, producing an instant cocaine-like high.

“Diseases of the mind are not exactly the same as diseases of the body,” Schwartz says. “The mind deserves special treatment, special consideration. And putting electrodes in a person’s brain to do something about their patterns of behavior is doing something dangerous.”

Greenberg argues that it’s wrong to “punish” the sick by denying them treatment just because someone might misuse it. Instead, he prefers to work with professional societies, and through speeches and editorials, to set standards for the procedure. He acknowledges, though, that there are few controls in place. Neurosurgeons can easily perform deep brain stimulation, but most lack the psychiatric training needed to identify appropriate candidates or follow their progress for years.

James P. McNulty, a national advocate for the mentally ill who served on the special ethics panel that reviewed the deep-brain study, approached the experiment with trepidation. Ultimately, he concluded that it promised more benefit than harm.

“I’ve seen up close and personal way too much suffering with mental illness to say we should just let this go,” says McNulty, a Burrillville resident who works for Magellan Health Care and also serves as vice chairman of the national consumer council of the National Alliance for the Mentally Ill.

McNulty knows mental illness firsthand. He has bipolar disorder, so he doesn’t need an electrical device to hurl him from grief to glee and back: his brain can do that on its own.

“Very clearly there’s an electro-mechanical part of us,” McNulty says. Brain injury can change personality, and diseases like Alzheimer’s can destroy it. Where, then, does the self reside?

“We think of ourselves as rational, autonomous beings,” McNulty says. “I’m kind of aware of just how plastic we are. People who haven’t experienced a mental illness or extreme mood swings I don’t think understand how tenuous our hold on reality is.”

WHATEVER THE power of deep brain stimulation, one thing was clear in the months after Mario Della Grotta’s surgery: it was no magic bullet. Twenty years of illness cannot be so quickly erased, and Della Grotta continued to struggle.

On March 12, 2001, his daughter, Kaleigh, was born. Four months later, Sheri went back to work and Mario stayed home with the baby. In the morning he spooned cereal into her mouth. But when the white globs inevitably dribbled down her chin, he would have to wash her face. Another spoonful. Another washing. By the time he was done feeding her breakfast, it was lunchtime.

Then there was the matter of the batteries that power Della Grotta’s implants. Batteries run out. Each time it happened, Della Grotta would feel worse within minutes.

Once an airport metal detector killed them. By the time he was on the plane, he found himself checking his money, retracing mentally what he’d spent. Over the next five years, Della Grotta had his batteries replaced six times, requiring outpatient surgery each time.

Della Grotta went back to school two years after receiving the implant, working toward a degree in paralegal studies at Johnson & Wales University. Once he had to drop a course because it involved writing a 25-page paper. Writing was still all but impossible. He would a write a paragraph, but if so much as one letter in his tiny script was misaligned, he felt compelled to start over.

Evans, his behavioral therapist, pushed him to write sloppily, to stop trying to memorize every word in the text, to spend less time studying. And gradually Della Grotta saw that as he eased up on his studying, his grades improved. He even managed to mail Evans an envelope written in the messiest script he could produce. It was so illegible that Della Grotta thought it wouldn’t arrive — but in fact the sloppy envelope has become part of his treatment record in Evans’ folder.

Meanwhile, Della Grotta was interviewing for jobs. But prospective employers looked askance at his years out of work. Had he been in prison? In drug rehab? Telling the truth, even an abbreviated version, did not put their minds at ease. One interviewer told him he would be a “liability” for the company.

Then something surprising happened. In early 2005, Della Grotta had his batteries replaced on a Friday, but Greenberg wasn’t available to turn them on. So Della Grotta went the weekend without stimulation. And he felt fine. When he saw Greenberg on Monday, they decided to let it be. He continued to attend school, and take care of his children — a second daughter, Nadia, was born on Jan 10, 2005 — with his brain implant lying dormant.

The implant alone could not fix Della Grotta, says Greenberg, but it enabled him to do the behavioral therapy that brings about the true, lasting brain repair. With what Greenberg called his “new and improved brain,” Della Grotta did not need the stimulation. He lasted three months like that, but then felt some symptoms returning, and Greenberg turned the device back on.

As he continued with the therapy, Della Grotta gradually improved. In May 2005, four years after the surgery, Della Grotta graduated from Johnson & Wales. He was able to take spontaneous trips rather than planning every move, and many of his obsessions abated. “If this was before surgery,” he told me one afternoon at a coffee shop, “I would be counting. ‘How much did I just spend?’ Now I can’t even tell you how much I spent. It’s almost too good to believe.”

Finally, last May, Della Grotta got a job — as an accountant at Rhode Island Mortgage, in Warwick. “My boss said, ‘You’re so organized, so detail-oriented,’ ” Della Grotta recalls. “I just told him I had OCD. He said, ‘That works to my advantage.’ ”

Greenberg calls Mario Della Grotta a success story, and says he’s not the only one. In the months after his operation, nine additional patients in Providence and Cleveland received implants as part of the experiment, and the majority improved with few side effects. Greenberg and others recently received a grant to do additional research into OCD and deep brain stimulation.

Dr. Scott Rauch, director of Massachusetts General Hospital’s Psychiatric Neuroimaging Research Program, says that deep brain stimulation may, in the long run, benefit more people than just those willing to have holes drilled in their heads. It could shed light on the poorly understood brain processes underlying mental illness, leading to more effective treatments — even, Rauch says, prevention and cure.

“It’s a very exciting time,” says Rauch, who will be working with Greenberg and Rasmussen on the new study. “We are poised as never before to really advance our understanding of underlying disease.”

Mario Della Grotta has certainly made his contribution to that understanding. And he believes he got plenty in return. Not long ago, it took him hours just to get out of bed. Now Della Grotta gets up every morning to go to a full-time job. Next month, he plans to start attending the Massachusetts School of Law; he hopes to eventually become a lawyer specializing in disability law. And he enjoys a close relationship with his wife and little girls. Without the implant, he says, “I would probably be a distant father.”

The other day I asked him whether he might have come this far anyway, even if he hadn’t had the surgery. He shook his head and breathed, “Oh, no.”

But Della Grotta, who turns 38 on Wednesday, knows he’s not cured, even with the stimulators running. He takes two medications and meets weekly with Evans, his behavioral therapist. He still struggles with perfectionism and a fixation on numbers. Sometimes he wakes early obsessing about his bank account. If he misplaces a shirt, his worry about that can snowball into a bout of checking and counting every article of his clothing. He estimates he still spends about five hours a day in mental calculations. “It’s a job,” he says.