The Tern Programme Study protocol for an implementation trial of a flexible, long-term psychosocial intervention for complex posttraumatic stress in young people.

Background: Complex Trauma (CT) is a term used to refer to multiple or prolonged traumatic experiences. Such experiences are often first encountered during childhood and may impact key developmental periods. CT is a risk for a broad range of deleterious physical, psychological, social, and occupational outcomes. The diagnosis of Complex Posttraumatic Stress Disorder (C-PTSD) has been proposed to capture the symptomatology resulting from CT exposure.In Australia, there are few publicly funded services that target, and are purposely designed to support, the mental health needs of young people with symptoms of complex post-traumatic stress (C-PTSD). The Tern Programme has been designed as a purpose-built model of care for providing mental health support to young people with C-PTSD.

Methods: This implementation trial will involve a longitudinal examination of Tern participants for a fixed 24-month period. Participants will be recruited from the young people referred to Tern at headspace centres in regional Australia where Tern operates. Eligible participants will have reported a history of complex trauma, and present with symptoms of C-PTSD. All participants will be invited to complete a series of surveys during their participation in the programme. Survey items will assess C-PTSD symptom change, quality of life and occupational functioning.The Tern model of care is delivered in a semi-structured format to accommodate a person-centred flexible approach. Fidelity will be monitored through the completion of a clinician post-session checklist and through group supervision.

Discussion: This study will provide the first quantitative data on the new Tern model of care and evaluate mental health and functional outcomes of its participants. If effective, Tern may be suitable for replication in other Australian or international youth mental health services where complex post-traumatic stress is prevalent.

Trial Registration: Australia and New Zealand Clinical Trials Registry (ANZCTR): ACTRN12621000079842p. Prospectively registered on 29 January 2021.

Abbreviations: CT = Complex Trauma; C-PTSD = Complex Posttraumatic Stress Disorder.