Open Dialogue: Development and Evaluation of a Social Network Intervention for Severe Mental Illness
ODDESSI
ODDESSI
ODDESSI is a large randomised control trial, researching the effectiveness of Open Dialogue in crisis and continuing mental health care within the National health Service in the UK.
ODDESSI findings and the Open Dialogue approach in Australia
In August 2026, ODDESSI, the world’s first large-scale randomised controlled trial (RCT) of Open Dialogue conducted within a mainstream public mental health system, was published in The Lancet Psychiatry.
About the trial
The ODDESSI trial was funded by the National Institute for Health Research (NIHR) and delivered across five NHS mental health trusts in London and the South of England. Led by Professor Stephen Pilling and a team of UK researchers, the trial followed 494 adults presenting in mental health crisis over two years. The trial tested Peer-supported Open Dialogue (PSOD), a variant of Open Dialogue that adds trained peer workers to clinical teams, deepening the network-based, collaborative model of care.
What it means for Australia
Until now, the strongest evidence for Open Dialogue came from Western Lapland, Finland, where the approach was developed: a small, tightly integrated health system very different from Australia’s. ODDESSI tested Open Dialogue inside a large, complex, mainstream public system instead, one that shares pressures familiar to Australia’s own services: high demand, stretched workforces, and a crisis-driven pathway into care.
The findings
On ODDESSI’s primary measure, the time to relapse after initial recovery, outcomes were similar between the two groups, and the difference was not statistically significant. Further evidence is needed.
Alongside this primary finding, ODDESSI recorded a number of secondary outcomes that were more favourable for people who received Open Dialogue compared to standard care:
- The odds of being admitted to hospital for severe mental illness were three times less.
- The proportion of people who spent any days in hospital, across the whole two-year follow-up, reduced by 52%.
- The odds of being re-referred to a crisis or secondary care service were halved.
- Patient-defined recovery (people’s rating of their relationships, work, study and other self-rated markers) improved.
- Quality of life, relating to overall health, improved.
- Patient satisfaction with the care they received was higher.
“Mental health services are under enormous pressure, with many people stuck in a revolving door of crisis care and hospital admissions. Too often care is disjointed, families are left out and not enough time is spent on forging a deep and lasting therapeutic relationship in our services. The ODDESSI trial shows that when care is built around relationships, mutuality, continuity and shared decision-making, people report better recovery, better quality of life and better experiences of care, while at the same time making far less use of inpatient or crisis services.”
— Professor Russell Razzaque, ODDESSI Co-author, Consultant Psychiatrist at NELFT and Professor of Relational Psychiatry at SOAS.
What ODC is doing
The Open Dialogue Centre (ODC) is building the field for community-based mental health transformation in Australia, supporting services and communities to shift from a crisis-driven, medicalised response toward one built on relationships, agency and connection in community.
ODDESSI tested Open Dialogue within mental health services. In Australia, ODC is collaborating with community partners in Victoria, New South Wales and Queensland to embed Open Dialogue not only within a single service, but across several services working together within a community.
With community partners and young people, ODC has developed a national Impact Framework to track activity, reach and outcomes, contributing to the global evidence base for Open Dialogue.
For more information download ODC’s summary sheet here.
