Characterising the clinical heterogeneity and aetiology of Avoidant Restrictive Food Intake Disorder

Avoidant Restrictive Food Intake Disorder (ARFID), introduced to the DSM-5 diagnostic classification system in 2013, is a severe feeding and eating disorder marked by food avoidance and restricted intake, with a prevalence of 1-2%, and serious consequences which can include malnutrition, psychosocial distress and in-patient ward tube feeding. ARFID is heterogeneous in clinical presentation, encompassing symptoms such as diminished appetite, sensory-based food aversion, and fear of adverse consequences associated with eating. This heterogeneity has raised important and related questions about the conceptualisation of ARFID. 1. Should ARFID be conceptualised as either a neurodevelopmental condition, an anxiety disorder, a consequence of metabolic imbalance or a combination of these? 2. Does ARFID consist of a collection of aetiologically distinct subtypes which will require different treatment approaches? To address this, I will use large-scale cohorts to: 1. Characterise the heterogeneity of ARFID 2. Derive data-driven subtypes 3. Investigate aetiology, and whether subtypes can be aetiologically distinguished With ARFID research in its infancy, now is the time to answer these fundamental questions to inform future aetiological research and intervention approaches. I will work with individuals living with ARFID, services, and the charity Beat, throughout the fellowship to co-produce evidence-based resources, and influence service development.