6846 Concept of neurodevelopmental comorbidities: do we need a paradigm shift?

Objectives Neurodevelopmental disorders (NDD) often co-occur in clusters with a wider range of emotional, behavioural, and intellectual disorders. This common scenario has led some authors to introduce the concept of ESSENCE (Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations) (Gillberg, 2010) and a more unified terminology of NDEBID (Neurodevelopmental, Emotional, Behavioural and Intellectual disorders (Ogundele & Morton, 2022). NDEBIDs include a number of long-term conditions caused by dysfunctions of the early developing brain and or neuromuscular system leading to functional limitations. They include Autism Spectrum Disorder (ASD), Attention Deficit/Hyperactivity Disorder (ADHD), Tic Disorders, Developmental Language, Coordination Disorders and Intellectual Disability. We aimed to explore recent research on the comorbidity of common NDD, including aetiopathogenesis, concepts of diagnosis and implications for management strategies. Methods A systematic review of the literature was conducted on indexed databases of Ovid, PubMed, CINAHL, and the Cochrane Database of Systematic reviews, using a combination of keywords including 'childhood', 'neurodevelopmental', 'comorbidities', and 'co-occurrence'. Results The concept of comorbidity in physical and psychological disorders is relatively new and was introduced in the 1970s. Most NDEBID conditions have unknown aetiology and lack circumscribed psychopathology but typically based solely upon description of psychopathology. They often share symptoms and manifestations that are not mutually exclusive to any one discrete condition. Attempts at classifying various NDD has gone through a wide range of complex and sometimes controversial changes over the past five decades, with the WHO's International Classification of Diseases (ICD) and the American Psychiatric Association's Diagnostic and Statistical Manual (DSM) emerging as the commonest clinical and research standards. Four alternative hypotheses have been published to conceptualise how comorbid NDEBID are classified and understood: (1) Neuroconstructivism, (2) 'Neurodevelopmental Disability', (3) 'Overarching Spectrum of ASD-ADHD disorder' and (4) 'Severe Autism Spectrum' concepts. Neuroconstructivists views the early developing brain as an interacting system where disturbance in one area has a cascading effect on a range of other domains. This encourages a more generic approach to description and identification of NDEBID. Dorothy Bishop introduced the term 'Neurodevelopmental Disability' as a generic term to describe any NDEBID condition, with the specific type of difficulties listed and described in more detail. An overarching 'Spectrum of ASD-ADHD' disorder has been proposed for CYP presenting with wide range of symptoms common to both conditions as a continuum of difficulties, rather than as separate discrete diagnoses. ASD and ADHD have many characteristics in common, including inheritability and genetic overlap, similar but qualitatively diverse neuropsychological 'deficits'. Other researchers have conceptualised the idea of comorbid ASD/ADHD as a form of 'severe Autism' rather than two separate diagnoses, with a peculiar attentional trait and disabling functional effects. Conclusion Embracing the concept of a wider neurodevelopmental spectrum disorder would encourage practitioners to offer a more wholistic therapeutic approaches to diagnosis and interventions, and help patients and their families avoid the agony of widespread service fragmentation. Other researchers have favoured a wider application of the hierarchical descending order of NDEBID conditions, similar to the classification of psychiatric disorders used in ICD-10.