Symptoms and Development of Anxiety in Children With or Without Intellectual Disability

Abstract

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.

ACKNOWLEDGMENTS

This article was based on the activities of the Collaborative Family Study, supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Grant number 34879-1459 (Drs. Bruce L. Baker, Jan Blacher, and Keith Crnic PIs). We are indebted to our staff and doctoral student colleagues.

Notes

Note: Scores reported from child age 5 years except where otherwise noted. TD=typical cognitive development; ID=intellectual disability; CBCL=Child Behavior Checklist.

^a n=92.

^b n=56.

†p<.10.

*p<.05.

**p<.01.

***p<.001.

Note: N for CBCL analyses=Age 5: 115 TD, 73 ID; Age 6: 112 TD, 74 ID; Age 7: 108 TD, 69 ID; Age 8: 102 TD, 57 ID; Age 9: 105 TD, 57 ID. N for DISC analyses=116 TD; 74 ID at all ages. DISC=Diagnostic Interview Schedule for Children; CBCL=Child Behavior Checklist; DSM=Diagnostic and Statistical Manual of Mental Disorders; TD=typical cognitive development; ID=intellectual disability.

Note: Positive B for ID-TD typical cognitive development status variable indicates the odds of having anxiety are greater for ID compared to TD. Negative B for family income indicates that the odds of having anxiety increase as family income decreases. Odds ratio (OR) indicates the percent greater likelihood of having anxiety for one status group over another (ID compared to TD if B is negative) and for each 1-level decrease in family income. For ease of interpretations, significant ORs where the odds are greater for ID compared to TD are bold. ID=intellectual disability; TD= ↑typical cognitive development; CBCL=Child Behavior Checklist; DISC=Diagnostic Interview Schedule for Children; CI=confidence interval.

^† p<.10.

*p<.05.

**p<.01.

***p<.001.

Note: Positive B for ID-TD Status variable indicates the odds of having anxiety are greater for ID compared to TD. Negative B for family income indicates that the odds of having anxiety increase as family income decreases. Odds ratio (OR) indicates the percentage greater likelihood of having anxiety for one status group over another (ID compared to TD if B is negative) and for each 1-level decrease in family income. For ease of interpretations, significant ORs where the odds are greater for ID compared to TD are bold. ID=intellectual disability; TD=typical cognitive development; CBCL=Child Behavior Checklist; DISC=Diagnostic Interview Schedule for Children; CI=confidence interval.

^a Zero typical cognitive development TD children at age 84 months met CBCL criteria for both Anxiety and ADHD, thus the OR is infinitely large.

†p<.10.

*p<.05.

**p<.01.

***p<.001.

Note: CBCL=Child Behavior Checklist; ID=intellectual disability; TD=typical cognitive development.

^a The ID-TD status coefficient specifies whether and by how much the ID coefficient is greater than or less than the TD coefficient.

*p<.05.

***p<.001.