SAN FRANCISCO — Dawn Jewell recently treated a patient haunted by a car crash. The patient had developed acute anxiety over the cross streets where the crash occurred, unable to drive a route that carried so many painful memories.

So Dr. Jewell, a psychologist in Colorado, treated the patient through a technique called exposure therapy, providing emotional guidance as they revisited the intersection together.

But they did not physically return to the site. They revisited it through virtual reality.

Dr. 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.”