A new therapy that transports patients into a virtual world has been found to help people with depression.
During the therapy, patients wear a headset that projects a life-sized, virtual avatar of themselves in front of them.
They "embody" the avatar, in that it responds to their movements.
The patients then see a second avatar, this time of a crying child, and are asked to comfort the virtual youngster.
In a new study, led by researchers at University College London, participants who had previously been diagnosed with depression were found to benefit from the experience.
During the study 15 people who were all being treated by the NHS for depression put on the headsets.
While they embodied the adult avatar, participants were instructed to express compassion towards the distressed virtual child.
As they talked to the child it appeared to gradually stop crying and respond positively to the compassion.
After a few minutes the patients were instead embodied in the virtual child and saw the adult avatar deliver their own compassionate words and gestures to them.
This brief eight-minute scenario was repeated three times at weekly intervals, and patients were followed up a month later.
The researchers found that those involved in the study learned to be more compassionate towards themselves and as a result their symptoms of depression improved.
"People who struggle with anxiety and depression can be excessively self-critical when things go wrong in their lives," study lead Professor Chris Brewin said in a statement.
"In this study, by comforting the child and then hearing their own words back, patients are indirectly giving themselves compassion.
"The aim was to teach patients to be more compassionate towards themselves and less self-critical, and we saw promising results.
"A month after the study, several patients described how their experience had changed their response to real-life situations in which they would previously have been self-critical."
The researchers have said more testing is needed before this type of therapy becomes standard for people with mental health issues.
Co-author Professor Mel Slater added: "We now hope to develop the technique further to conduct a larger controlled trial, so that we can confidently determine any clinical benefit.
"If a substantial benefit is seen, then this therapy could have huge potential. The recent marketing of low-cost home virtual reality systems means that methods such as this could potentially be part of every home and be used on a widespread basis."
The full study is published in the British Journal of Psychiatry Open.