SAN FRANCISCO – Dawn Jewell recently treated a patient haunted by a car crash. The patient was unable to drive a route that carried so many painful memories.

So Jewell, a psychologist in Colorado, treated the patient through a technique called exposure therapy, providing guidance as they revisited the intersection. But they did not physically return to the site. They revisited it through virtual reality.

Jewell is among a handful of psychologists testing a new service from a Silicon Valley start-up called Limbix that offers exposure therapy through Daydream View, the Google headset that works in tandem with a smartphone.

"It provides exposure in a way that patients feel safe," she said. "We can go to a location together, and the patient can tell me what they're feeling and what they're thinking."

The service recreates outdoor locations by tapping into another Google product, Street View, a vast online database of photos that delivers panoramic scenes of roadways and other locations. Using these virtual street scenes, Jewell has treated a second patient who struggled with anxiety after being injured by another person outside a local building.

The service is also designed to provide treatment in other ways, like taking patients to the top of a virtual skyscraper so they can face a fear of heights or to a virtual bar so they can address an alcohol addiction.

Backed by the venture capital firm Sequoia Capital, Limbix is less than 1 year old. The creators, including its chief executive and co-founder, Benjamin Lewis, worked in the seminal virtual reality efforts at Google and Facebook.

The hardware and software is still very young, but Limbix builds on more than two decades of research and clinical trials. At a time when much-hyped headsets like the Daydream and Facebook's Oculus are struggling to find a wide audience, psychology is an area where technology and medical experts believe this technology can be a benefit. And the headsets could bring this kind of therapy to a wider audience.

As far back as the mid-1990s, clinical trials showed that this kind of technology could help treat phobias and other conditions, like post-traumatic stress disorder. Traditionally, psychologists would help patients imagine they are facing a fear. Virtual reality takes this a step further. "We feel pretty confident that exposure therapy using VR can supplement what a patient's imagination alone can do," said Skip Rizzo, a clinical psychologist at the University of Southern California.

Limbix just started offering its tools to therapists outside its initial test. The service is free for now, with the company planning to sell more advanced tools at some point.

Jewell said Limbix allowed patients to face their anxieties in more controlled ways than they otherwise could. Experts caution that the technology requires the guiding hand of trained psychologists while still in development.