Feasibility of an adjunctive INtervention for Debilitating symptom complexes attributed to ticks (FIND): study protocol for a randomised, waitlist-controlled feasibility trial

BACKGROUND: Debilitating Symptom Complexes Attributed to Ticks (DSCATT) is a new term for an unexplained Australian syndrome-people who suffer from a chronic, multifaceted and debilitating illness, characteristically attributed to tick bites, but in a country without endemic Lyme disease. Despite the profound morbidity of DSCATT, no single causative agent has been identified and there are no recognised treatments for the illness at present. An increasing body of evidence shows psychological therapies such as Acceptance and Commitment Therapy (ACT) can be effective in reducing symptom-related disability and improving quality of life for other unexplained syndromes. Here we present a study protocol to assess the feasibility of an ACT-informed intervention for patients suffering from DSCATT, to be used adjunctively to their pre-existing healthcare. The study aims to assess the acceptability, practicality and demand for the treatment. Additionally, we will examine the effects of therapy on participants' health and well-being, its safety, potential mediators of response to therapy and its preliminary cost-effectiveness. METHODS: We will assess the feasibility of a 32-week, randomised, waitlist-controlled, parallel convergent mixed-methods pilot trial for DSCATT. Participants will be randomised in a 1:1 ratio to receive either 16 sessions of ACT-informed therapy adjunctive to their pre-existing healthcare, delivered one-to-one with a trial therapist within a 20-week period or be assigned to the waitlist control group where they will continue their treatments as usual. We will collect quantitative and qualitative data to address study aims, with retention rate being the primary feasibility outcome. ETHICS AND DISSEMINATION: The study has ethical approval from Austin Health Human Research Ethics Committee (HREC). The outcomes will be published in peer-reviewed journals. Data from participants who have given extended consent will be available for other HREC-approved studies. TRIAL REGISTRATION NUMBER: ACTRN12623000372684, prospectively registered 13 April 2023, URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=385579&isReview=true; the last participant is expected to complete in November 2026.