LONG BEACH, California (CNN) -

It seems simple: Walk to the refrigerator and grab a drink.

But Brett Larsen, 37, opens the door gingerly -- peeks in -- closes it, opens it, closes it and opens it again. This goes on for several minutes.

When he finally gets out a bottle of soda, he places his thumb and index finger on the cap, just so. Twists it open. Twists it closed. Twists it open.

"Just think about any movement that you have during the course of a day -- closing a door or flushing the toilet -- over and over and over," said Michele Larsen, Brett's mother.

"I cannot tell you the number of things we've had to replace for being broken because they've been used so many times."

At 12, Larsen was diagnosed with obsessive-compulsive disorder, or OCD. It causes anxiety, which grips him so tightly that his only relief is repetition. It manifests in the smallest of tasks: taking a shower, putting on his shoes, walking through a doorway.

There are days when Larsen cannot leave the house.

"I can only imagine how difficult that is to live with that every single living waking moment of your life," said Dr. Gerald Maguire, Larsen's psychiatrist.

In a last-ditch effort to relieve his symptoms, Larsen decided to undergo deep brain stimulation. Electrodes were implanted in his brain, nestled near the striatum, an area thought to be responsible for deep, primitive emotions such as anxiety and fear.

Larsen's OCD trigger

Larsen says his obsessions and compulsions began when he was 10, after his father died.

"I started worrying a lot about my family and loved ones dying or something bad happening to them," he said. "I just got the thought in my head that if I switch the light off a certain amount of times, maybe I could control it somehow.

"Then I just kept doing it, and it got worse and worse."

"Being OCD" has become a cultural catchphrase, but for people with the actual disorder, life can feel like a broken record. With OCD, the normal impulse to go back and check if you turned off the stove, or whether you left the lights on, becomes part of a crippling ritual.

The disease hijacked Larsen's life (he cannot hold down a job and rarely sees friends); his personality (he can be stone-faced, with only glimpses of a slight smile); and his speech (a stuttering-like condition causes his speaking to be halting and labored.)

He spent the past two decades trying everything: multiple medication combinations, cognitive behavioral therapy, cross-country visits to specialists, even hospitalization.

Nothing could quell the anxiety churning inside him.

"This is not something that you consider first line for patients because this is invasive," said Maguire, chair of psychiatry and neuroscience at the University of California Riverside medical school, and part of the team evaluating whether Larsen was a good candidate for deep brain stimulation. "It's reserved for those patients when the standard therapies, the talk therapies, the medication therapies have failed."

Deep brain stimulation is an experimental intervention, most commonly used among patients with nervous system disorders such as essential tremor, dystonia or Parkinson's disease. In rare cases, it has been used for patients with intractable depression and OCD.

The electrodes alter the electrical field around regions of the brain thought to influence disease -- in some cases amplifying it, in others dampening it -- in hopes of relieving symptoms, said Dr. Frank Hsu, professor and chair of the department of neurosurgery at University of California, Irvine.

Hsu says stimulating the brain has worked with several OCD patients, but that the precise mechanism is not well understood.

The procedure is not innocuous: It involves a small risk of bleeding in the brain, stroke and infection. A battery pack embedded under the skin keeps the electrical current coursing to the brain, but each time the batteries run out, another surgical procedure is required.

'I feel like laughing'

As doctors navigated Larsen's brain tissue in the operating room -- stimulating different areas to determine where to focus the electrical current -- Larsen began to feel his fear fade.

At one point he began beaming, then giggling. It was an uncharacteristic light moment for someone usually gripped by anxiety.