The COSI study: Exploring effectiveness of a group-based intervention for mothers in perinatal mental health services


The COSI study is a 4-year multi-site randomised controlled trial to investigate the clinical and cost effectiveness of a 10-session, group-based programme called Circle of Security Parenting (COS-P) for birthing parents in NHS perinatal mental health services (PMHS). The COS-P programme is designed to help parents manage their difficult emotions and understand the impact of this on the parent-infant relationship. 

This research aims to understand whether COS-P is more effective than treatment as usual (TAU) in improving mental health difficulties and the quality of parent-infant relationships. Secondary objectives of the study are to explore observed parenting sensitivity, emotion regulation skills, attachment security and infant development in addition to assessing cost-effectiveness, service-user and practitioner acceptability.

As part of several PhD projects, researchers are also reviewing the literature to understand the clinical effectiveness of group interventions for parents with mental health difficulties and children under 5. The results of the systematic review will help to evaluate the effective components and overall impact of group interventions implemented to this specific group of parents. Additionally, one of the PhD students on the projects is trying to learn more about the effects of conflict in parental relationships. 

This research is funded by the NIHR Health Technology Assessment (HTA) Programme.

Partners & Collaborators

Anna Freud National Centre for Children and Families (study sponsor)

University College London 

Imperial College London

University of Huddersfield

Mersey Care NHS Foundation Trust

Lead Investigator
Camilla Rosan (Anna Freud)
Investigating Team
Zoe Darwin (Huddersfield)
Victoria Cornelius (Imperial)
Ed Waddingham (Imperial)
Matyas Szigeti (Imperial)
Pasco Fearon (UCL)
Lani Richards (Anna Freud)
Kim Alyousefi-van Dijk (Anna Freud)
Daphne Babalis (Imperial)
Nic Horley (West London NHS Trust)
Ruth O’Shaughnnesy (North West Boroughs Healthcare NHS Foundation Trust)
Aylin Aras
Amy Shearson
Jude Field
Radhika Joshi
Pasang Tamang
Grace Baptie
Lydia Barge
Gavin Slee
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