Symptoms and development of anxiety in children with or without intellectual disability.

The purpose of this study was to examine group differences in presentation and trajectory of anxiety symptoms and disorders in children with moderate to borderline intellectual disability (ID) and children with typical cognitive development (TD). Examined anxiety disorders and symptoms in children with ID (n=74) or TD (n=116) annually from ages 5 through 9 using a parent structured interview and questionnaire. Logistic regression was used to examine odds of meeting anxiety criteria and hierarchical linear modeling was used to examine anxiety trajectory. Children with ID had significantly higher rates of clinical levels of anxiety on the Child Behavior Checklist at ages 8 and 9 and higher rates of separation anxiety disorder at age 5 compared to those with TD. Children with ID were also more likely to have externalizing problems co-occurring with anxiety. The rate of increase of anxiety symptoms over time was positive and similar in the two groups, and neither group showed sex differences in anxiety rates. Results suggest that children with ID have both higher rates of anxiety across time and are delayed in showing typical decreases in separation anxiety in early childhood. Implications for intervention are discussed in terms of the importance of screening for and treating anxiety in children with ID.