Anxiety in Autism and Rare Genetic Syndromes Associated with Intellectual Disability

Abstract

Many individuals with intellectual disability (ID), particularly those with moderate to profound ID, have co-occurring autism and/or a diagnosis of a genetic syndrome. Autism and/or a genetic syndrome diagnosis can confer risk for anxiety. However, most anxiety research focuses on autistic individuals without ID, or individuals with mild ID, resulting in an unrepresentative evidence base. Research is needed to explore anxiety in these underresearched groups who are at risk of anxiety. This thesis aims to address this gap using a variety of methodological approaches. Chapter one presents a critical synthesis of literature to inform the thesis aims. Chapter two presents a systematic review and meta-analysis detailing the prevalence of anxiety symptomatology and diagnosis in genetic syndromes associated with ID. The chapter highlights varying anxiety risk across groups and considers factors that may give rise to varying prevalence estimates. Chapter three utilises questionnaire methodology to identify correlates of anxiety in individuals with moderate to profound ID, identifying potential causal mechanisms that cut-across groups. Intolerance of uncertainty was consistently associated with anxiety. Chapter four utilises semi-structured interviews with parents/carers and clinicians to delineate anxiety presentation in a group at high risk of anxiety, autistic individuals with ID. The chapter also explores current anxiety assessment in practice and the development of new assessments. Behaviours indicating potential anxiety included increased vocalisation, avoidance, and behaviours that challenge. Changes to routine trigger anxiety. Clinicians emphasised identifying an individual’s baseline behaviour, knowing an individual well and ruling out other forms of distress. Chapter five documents a direct assessment and fine-grained analysis, identifying behavioural markers of anxiety in autistic individuals. During anxiety-provoking situations, social gaze, rigidity, negative and positive affect were observed. Negative affect was accompanied by engagement in repetitive behaviour. Chapter six discusses implications and directions for further research. The thesis will inform early identification and intervention.