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

The Circle of Security-Parenting (COS-P) intervention (formerly COSI) – developed to support parents experiencing perinatal mental health difficulties – shows promising findings in intervention effectiveness and user acceptability.

We are assessing the use of COS-P within NHS Perinatal Mental Health Services (PMHS) in England – exploring whether COS-P is more effective than usual courses of treatment in improving maternal mental health difficulties and the quality of parent-infant relationships.

We are also studying the impact of COS-P on parenting sensitivity, emotion regulation skills, infant development, and attachment security and whether it is acceptable to parents and NHS staff involved in the delivery.

This study will improve the support available for birthing parents experiencing perinatal mental health difficulties by providing valuable information regarding the effectiveness and acceptability of COS-P in this setting, and cost-effectiveness of delivering it within the NHS Participant recruitment will finish in October 2023 and the first results are expected in 2025.

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

University College London 

Imperial College London

University of Huddersfield

Mersey Care NHS Foundation Trust