Researchers discovered that virtual reality allows highly paranoid people to face situations that they normally fear.
The study shows how virtual reality simulations allows the patients to learn that routine situations that terrified them were actually safe.
And some severely paranoid patients showed “major reductions” in their paranoia after just one 30 minute virtual reality session.
The study, conducted by Oxford University researchers, combines psychological treatment techniques with state-of-the-art virtual reality social situations to reduce paranoia.
Up to one in 50 people have severe paranoia, usually as a central feature of severe mental health disorders such as schizophrenia.
Patients show extreme mistrust of other people, believing that others are deliberately trying to harm them.
The condition can be so debilitating that sufferers may be unable to leave their house.
Ways of coping - such as avoiding social situations, reducing eye contact or making any social interactions as short as possible - actually worsen the situation since they reinforce paranoid fears.
Patients come to believe that they avoided harm because they used such so-called ‘defence behaviours.’
The researchers, whose findings were published in the British Journal of Psychiatry, wanted to test whether patients could ‘re-learn’ that a situation was safe, by experiencing situations they feared without using their defence behaviours.
The researchers said being in a situation they fear is very difficult for many patients, since it causes “intolerable” anxiety.
To overcome the challenge the researchers used virtual reality to recreate social situations which patients found fearful.
Thirty patients attending treatment services took part in the study. They all went into virtual reality simulations with increasing numbers of computer characters - seeing many people at the same time would normally make these patients quite anxious.
But the participants were told that by staying in the situations, they would relearn that they were safe. A train ride and a lift scene were used.
One group were encouraged to use their normal defence behaviours: they were told that it would work a bit like getting into cold water, that when you first get in it feels uncomfortable, but after a while you get used to it, as long as you stay in.
The other patients were encouraged to drop their defences and try to fully learn that they were safe by approaching the computer characters and looking at them - holding long stares or standing toe-to-toe with the avatars.
The patients who fully tested out their fears in virtual reality by lowering their defences showed “very substantial” reductions in their paranoid delusions.
After the virtual reality therapy session, more than half of the patients no longer had severe paranoia at the end of the testing day.
The researchers said there were even benefits for those who confronted situations they feared in virtual reality while still using their defences: around 20 per cent of the group no longer having severe paranoia at the end of the testing day.
Patients who fully tested out their fears in virtual reality were later much less distressed even when in a real life situation, such as going to the local shop.
Study leader Professor Daniel Freeman, who is also a clinical psychologist at Oxford Health NHS Foundation Trust, said: “Paranoia all too often leads to isolation, unhappiness, and profound distress.
“But the exceptionally positive immediate results for the patients in this study show a new route forward in treatment.
“In just a 30 minute session, those who used the right psychological techniques showed major reductions in paranoia.
“It’s not easy work for patients, since lowering defences takes courage. But as they relearned that being around other people was safe we saw their paranoia begin to melt away.
“They were then able to go into real social situations and cope far better. This has the potential to be transformative.”
Research team member Professor David Clark said: “There is growing evidence that psychological treatments can have a major beneficial impact on the lives of people suffering from psychosis.
“Virtual reality assisted treatment has great potential because, as the price of the equipment makes it more accessible, much treatment could be delivered in people’s homes.”
Dr Kathryn Adcock, of the Medical Research Council which funded the study, added: “Virtual reality is proving extremely effective in the assessment and treatment of mental health problems.
“This study shows the potential of its application to a major psychiatric problem.
“There is a lot of work to do be done in testing the approach for treating delusions, but this study shows a new way forward.”