It's well known that community singing has positive benefits for health - including increased lung capacity, stress reduction and even boosting the immune system.
Now the first study to find evidence that choral singing has sustained benefits for people with mental health problems has been published.
Professor Stephen Clift, who's the Director of Research at the Sidney De Haan Centre for Arts and Health in Canterbury, says that as well as being fun, the social contact and structure provided by the regular rehearsals play a part in improving wellbeing.
He's evaluated the impact on the singers by asking them to complete questionnaires used widely to monitor psychological progress. Over 8 months he said there had been dramatic improvements.
The Mustard Seed Singers were the inspiration behind 8 other new choirs for people with a variety of enduring mental health problems.
The group is led by Elle Caldon, who has bipolar affective disorder. She's been in hospital a couple of times and has sung all her life.
Another singer Teresa Pierce, who has bipolar depression, says if she gets low she would normally "shut down" and not mix with other people. But she still goes to sing as it lifts her mood.