It’s a sunny day on a city street as a green bus pulls up by the kerb. Onboard, a handful of passengers sit stony-faced as you step up to present your pass. But you cannot see your body – only a floating pair of blue hands.

It might sound like a bizarre dream, but the scenario is part of a virtual reality (VR) system designed to help people with agoraphobia – those for whom certain environments, situations and interactions can cause intense fear and distress.

Scientists say the approach enables participants to build confidence and ease their fears, helping them to undertake tasks in real life that they had previously avoided. The study also found those with more severe psychological problems benefited the most.

“It leads to a real step-change in people’s lives,” said Prof Daniel Freeman, the lead researcher in the work, from the psychiatry department at the University of Oxford.

The VR experience begins in a virtual therapist’s office before moving to scenarios such as opening the front door or being in a doctor’s surgery, each with varying levels of difficulty. Participants are asked to complete certain tasks, such as asking for a cup of coffee, and are encouraged to make eye contact or move closer to other characters.

Freeman said while the scenarios feel real, the computer-generated scenes allow participants to feel able to try something new or approach the situation differently. “There’s a little bit of the conscious bit [of the brain] going: ‘OK, it’s OK, I know it’s not real and therefore I can persist, try something new and do something differently,’” he said.

“That enables people to apply it in the real world. Basically, if you get over something in VR, you will get over in the real world.”

One participant revealed that before using the VR system he struggled with taking a bus to visit his father’s grave. “It was heartbreaking,” he said. However, after using VR system he gained confidence.

“It’s helped me for every aspect,” he said. “I’ve been able to get the bus to my dad’s grave, I’ve been able to put flowers down, spend a little bit of time there and get the bus back.”

Writing in the Lancet Psychiatry journal, Freeman and colleagues report how they randomly allocated 174 patients with difficulties going outside and psychosis to use the “gameChange” VR technology alongside their usual care. Another 172 patients were allocated to receive their usual care alone.

Participants in the VR group were given the opportunity to use the technology for approximately six sessions, each lasting 30 minutes, over the course of six weeks – although not all took part or completed all the sessions.

A mental health worker was in the room while each participant used the VR headset, whether in their home or in an NHS clinic, and worked with the participant to apply the learning, including by setting homework tasks between sessions.

The results show that six weeks after the trial began, those allocated to the VR therapy had a small but significant reduction in avoiding real-life situations because of agoraphobia, as well as less distress, compared with those who had only received their usual care. However, by six months there was no difference between the two groups.

But further analysis revealed that those who had severe agoraphobia benefited most, and for these people the effect was sustained at six months. Such patients were able to complete, on average, two more activities than before – such as going shopping or getting on a bus.

While the study cannot tease out the impact of the VR therapy from the mental health worker and their homework, Freeman said other tests had not shown changes in agoraphobia in this population from such homework tasks alone.

Freeman added that with VR headsets now costing about £300, it was becoming easier to send such devices to patients’ homes.

For the patient who wanted to be able to visit his father’s grave, the benefits have been much more wide-ranging than just completing tasks. “I’ve been able to go out, interact with a lot more people than what I ever expected,” he said. “I’m more confident in myself. I’m more confident around other people.”