Neurodevelopmental Problems in a Clinical Sample of Children with Anxiety Disorders

Abstract

Anxiety disorders are among the most common psychiatric conditions in childhood and adolescence, and may persist into adulthood. The development of anxiety disorders seems to be caused by a complex interaction between genetic and environmental factors. Children with neurodevelopmental disorders, such as specific language impairment and developmental coordination disorder, have been shown to exhibit an increased prevalence of anxiety disorders. However, the literature on neurodevelopmental disorders in children with anxiety disorders is sparse, rendering it unresolved whether the presence of neurodevelopmental disorders constitute an important problem among children with anxiety disorders.<br><br>

Objectives: The main objective of this thesis was to investigate the association between anxiety disorders and neurodevelopmental delays/disorders in children studied within a clinical setting. The more specific aims of investigation were: <ul><li>To compare the frequency and degree of motor impairment in a clinical sample of children with anxiety disorders, ADHD, and comorbid anxiety disorders and ADHD, compared with non-referred controls (paper I).</li> <li>To compare the frequency and degree of language impairment in a clinical sample of children with anxiety disorders, ADHD, and comorbid anxiety disorders and ADHD, compared with non-referred controls (paper II).</li> <li>To evaluate how anxiety symptoms, ADHD symptoms, and language ability predict social skills in a clinical sample of children with anxiet disorders with and without comorbid ADHD (paper II).</li> <li>To investigate the relationship between anxiety disorders, ADHD, and sluggish cognitive tempo (SCT) in a clinical sample of children with anxiety disorders, ADHD, and comorbid anxiety disorders and ADHD, compared with non-referred controls (paper III).</li> <li>To explore the association between SCT and some selected neurocognitive measures in a clinical sample of children with ADHD with and without comorbid anxiety disorders (paper III).</li></ul><br>

Material and methods: All three studies included in this thesis are based on the same sample. The sample consisted of a total of 141 children (90 males, 51 females) aged 7-13 years. The children were assigned to the following four groups: Referred children with anxiety disorders (n = 41), ADHD (n = 39), comorbid anxiety disorders and ADHD (n = 25), and controls (n = 36). The clinical children were recruited from referrals to two Norwegian outpatient child and adolescent psychiatric clinics over a 17-month period (autumn 2007 to spring 2009). Diagnoses were established using the Schedule for Affective Disorders and Schizophrenia for School-Aged children (6-18 years): Present and Lifetime Version (Kiddie-SADS P/L). Motor performance was assessed using the Motor Assessment Battery for Children (MABC) (paper I). Language skills were investigated with the verbal subtests of the Wechsler Abbreviated Scale of Intelligence (WASI) and the Children’s Communication Checklist (CCC-2) (paper II). Social skills were measured with the Social Skills Rating System (SSRS) (paper II). SCT was assessed by the SCT-17 questionnaire (paper III). Neurocognitive measures of reaction time, verbal memory, and spatial memory were obtained by testing the child (paper III).<br><br>

Results: We found that neurodevelopmental disorders, as conceptualized by motor and language impairment, were frequent among children with anxiety disorders. A total of 46 % of the children in the anxiety disorders group, and 36 % of the comorbid anxiety disorders and ADHD group exhibited motor impairment. Regarding language skills, 50 % of the children in the anxiety disorders group and 76 % of the children in the comorbid anxiety disorders and ADHD group exhibited scores consistent with language impairment. Taken together, neurodevelopmental disorders were found in 63 % of the children in the anxiety disorders group and 88 % in the comorbid anxiety disorders and ADHD group. In addition, we found an elevated level of sluggish cognitive tempo among children with comorbid anxiety disorder and ADHD compared with children who had ADHD without comorbid anxiety disorder.<br><br>

Conclusions: The three articles included in this thesis examine different areas of neurodevelopmental difficulties in referred children with anxiety disorders, compared with children with ADHD, children with comorbid anxiety disorders and ADHD, and non-referred controls. The main findings are that referred children with anxiety disorders exhibit a high prevalence of neurodevelopmental disorders (as conceptualized by significant motor or language impairment), and that referred children with comorbid anxiety disorders and ADHD exhibit a higher level of SCT than children with ADHD alone. The present findings underscore the importance of routinely assessing neurodevelopmental disorders in children with anxiety disorders. Furthermore, the findings provide a new perspective on the controversy regarding the utility and impact of SCT, by demonstrating that children with comorbid anxiety disorders and ADHD exhibit more SCT symptoms than children with ‘pure’ ADHD, regardless of subtype of ADHD or degree of hyperactivity/impulsivity symptoms.