The patients either joined a community group with activities such as sewing, yoga, sports and art, or partook in group therapy at a psychiatric hospital. (Agencies)
In both cases, patients responding to survey questions who did not identify strongly with the social group had about a 50 per cent likelihood of continued depression a month later, researchers said.
But of those who developed a stronger connection to the group and who came to see its members as 'us' rather than 'them,' less than a third still met the criteria for clinical depression after that time.
Many patients said the group made them feel supported because everyone was "in it together."
"We were able to find clear evidence that joining groups, and coming to identify with them, can alleviate depression," said Senior Fellow Alexander Haslam from the Canadian Institute for Advanced Research (CIFAR).
While past research has looked at the importance of social connections for preventing and treating depression, Haslam said it has tended to emphasise interpersonal relationships rather than the importance of a sense of group identity.
In addition, researchers haven't really understood why group therapy works. "Our work shows that the 'group' aspect of social interaction is critical," said Haslem, who conducted the study with lead author Tegan Cruwys and colleagues at the University of Queensland.
The finding was published in the Journal of Affective Disorders.
The patients either joined a community group with activities such as sewing, yoga, sports and art, or partook in group therapy at a psychiatric hospital.