Comorbidity in children and adolescents with autism spectrum disorder

Comorbidity is defined as the co-occurrence of two or more disorders in the same person (Matson & Nebel-Schwalm, 2007). Comorbidity in autism spectrum disorder (ASD) is a topic that has infrequently been addressed in the literature (Matson & Nebel-Schwalm, 2007). The aim of this thesis was to investigate comorbidity over a two-year time period, and to better understand the impact of GI symptoms and sleep problems on child behaviour and well-being, and parental well-being. Section 1 is about comorbidity in ASD. Section 2 is about gastrointestinal (GI) symptoms in ASD. Section 3 is about sleep problems in ASD. Section 4 is the general discussion. Study 1 investigated if there was a change in comorbid conditions over a two-year time period in children and adolescents with ASD (N=56). GI symptoms were found to persist in 84.4% of children and adolescents with ASD and sleep problems persisted in 91.5% of participants. Sleep problems did decrease as children got older, however for the majority, sleep problems did still reach clinical cut-off levels. There was a significant difference between over-eating from Time 1 to Time 2. Over-eating became more severe over time. The frequency of family history of autoimmune diseases and other medical and psychological conditions was examined. It was found that 98.2% of participants had some type of familial disorder and 92.9% of participants presented with a family history of autoimmune disease. Associations were found between family history of thyroid disorders and child GI symptoms. Relationships were found between family history of ulcerative colitis and Crohn’s disease, and child worry/depressed behaviour, repetitive behaviour, and sleep duration. Study 2 was an investigation of the relationship between GI symptoms and sleep problems, quality of life, challenging behaviour, comorbid psychopathology, social responsiveness, family medical history, sensory problems, behavioural and educational interventions, and complementary and alternative (CAM) interventions in children and adolescents with ASD (N=409). Children and adolescents with GI symptoms were found to have more sensory issues, challenging behaviour, comorbid psychopathology, sleep problems, more social deficits, and lower quality of life than children and adolescents without GI symptoms. Study 3 was an investigation of the relationship between child GI symptoms and parental well-being. It aimed to explore the relationship between GI symptoms and parental stress, anxiety, depression, quality of life, and social support in parents of children and adolescents with ASD (N=409). Parents of children and adolescents with GI symptoms experienced more parenting stress, lower quality of life, and lower perceived social support than did parents of children and adolescents without GI symptoms. Study 4 investigated the relationship between sleep problems and GI symptoms, quality of life, challenging behaviour, comorbid psychopathology, social responsiveness, sensory problems, behavioural and educational interventions, and complementary and alternative (CAM) interventions in children and adolescents with ASD (N=409). Children and adolescents with sleep problems had more GI symptoms, aggressive/destructive behaviour, sensory issues, comorbid psychopathology, and lower quality of life than children and adolescents without sleep problems. Study 5 investigated the relationship between child sleep problems and parental well-being, including parental sleep. It also investigated the relationships between parental sleep and parental stress, anxiety, depression, quality of life, and social support in parents of children and adolescents with ASD (N=409). Parents of children and adolescents with sleep problems experienced more parenting stress, more anxiety and depression, and lower quality of life than did parents of children and adolescents without sleep problems. Child sleep problems were correlated with parent sleep problems. Study 6 incorporated an objective measure of sleep, actigraphy, and a typically developing control group. Study 6 investigated child and parent sleep using actigraphy in children and adolescents with ASD (n=11) and their parents, and typically developing children and adolescents (n=11) and their parents. Study 6 investigated comorbid conditions in children and adolescents with ASD in comparison with typically developing children and adolescents. It was found that there were no significant differences between children and adolescents with ASD and their parents, and typically developing children and adolescents and their parents, on actigraphy variables. Significant differences were found between children and adolescents with ASD and typically developing children and adolescents in subjective sleep problems, behaviour problems, sensory issues, comorbid psychopathology, and quality of life. Significant differences were found between parents of children and adolescents with ASD and parents of typically developing children and adolescents, in subjective sleep quality, stress, anxiety, depression, and quality of life. Clinical implications and implications for future research were discussed in relation to the findings of the thesis. This thesis supports the need for screening and diagnosis of comorbid conditions. Screening for and diagnosing comorbid conditions, this will facilitate investigation of the most effective treatment options for individuals with ASD. Treating comorbid conditions may have direct implications on child behaviour and the quality of life of both children and adolescents with ASD and their parents.2020-10-0