Anxiety disorders in children and adolescents with autistic spectrum disorders: a meta-analysis

Authors:
VAN STEENSEL Francisca J. A., BÖGELS Susan M., PERRIN Sean
Journal article citation:
Clinical Child and Family Psychology Review, 14(3), September 2011, pp.302-317.
Publisher:
Springer US

Meta-analysis of data from 17 studies revealed that 40% of young people with autistic spectrum disorders have comorbid anxiety disorders; the prevalence of specific anxiety disorder subtypes are also reported. There was a high degree of heterogeneity between studies. Some significant moderating effects were identified but caution is urged in interpreting the results. A number of limitations are discussed including the use of instruments to assess anxiety that were designed to be used in typically developing children.

Extended abstract:
Author


VAN STEENSEL Francisca J. A.; BÖGELS Susan M.; PERRIN Sean;

Title

Anxiety disorders in children and adolescents with autistic spectrum disorders: a meta-analysis.

Journal citation/publication details

Clinical Child and Family Psychology Review, 14(3), September 2011, pp.302-317.

Summary

Meta-analysis of data from 17 studies revealed that 40% of young people with autistic spectrum disorders have comorbid anxiety disorders; the prevalence of specific anxiety disorder subtypes are also reported. There was a high degree of heterogeneity between studies. Some significant moderating effects were identified but caution is urged in interpreting the results. A number of limitations are discussed including the use of instruments to assess anxiety that were designed to be used in typically developing children.

Context

The prevalence of comorbid symptoms of anxiety, which contribute to functional impairment in young people with autistic spectrum disorders, has been reported to be highly variable, ranging from 11% to 84%. The aim of this systematic review and meta-analysis was to estimate the prevalence of specific anxiety disorders in this population and ‘evaluate the factors influencing the observed heterogeneity for rates of anxiety reported in the literature’.

Methods

What sources were searched?
Four electronic databases, PsycINFO, PubMed, Web of Science, and ERIC were searched. The reference lists of potentially relevant articles were hand searched for additional studies.

What search terms/strategies were used?
Terms for autistic spectrum disorders including ‘autism’, ‘asperger’, ‘pervasive development disorder’, and ‘PDD’ were used in combination with terms for anxiety disorder such as ‘anxiety’, ‘anxious’, ‘comorbid disorder’, ‘comorbidity’, ‘psychiatric disorder’, and ‘psychological disorder’. Details of specific search strategies are not presented and there is no indication of when the searches were carried out.

What criteria were used to decide on which studies to include?
Studies had to report on the number of children with an autistic spectrum disorder diagnosis and DSM-IV anxiety disorder, and/or the number of participants above the clinical cut-off for anxiety on a standardised measure of anxiety. The mean age of the population sample had to be below 18 years. Reviews were excluded.

Who decided on their relevance and quality?
Abstracts were initially screened by the first author. There is no indication that study quality was assessed.

How many studies were included and where were they from?
Thirty-one of the 86 studies retrieved from the searches were found to meet all of the inclusion criteria and are included in the systematic review and meta-analysis. The settings of the studies are not reported.

How were the study findings combined?
The percentage of children within each of the three categories of Asperger’s spectrum disorder i.e., autistic disorder, Asperger’s syndrome, and pervasive developmental disorder not otherwise specified (PDD-NOS), was calculated. Prevalence rates for anxiety in general, and for specific anxiety disorders were also calculated. Coding was carried out by the first author and a second coder, both working independently. Disagreements were discussed by the two coders until consensus was reached. Meta-analyses were conducted using a fixed effects and a random effects model. Mean effect size are reported for anxiety in general and each specific anxiety disorder examined. Moderator analyses were conducted for method of assessment, mean age, mean IQ, and each of the three autistic spectrum disorder subtypes.

Findings of the review

In all, 2,121 children and adolescents were included in the meta-analyses. The prevalence rate for any anxiety disorder or clinically elevated levels of anxiety was 39.6%. The most common anxiety disorder was specific phobia (29.8%), followed by obsessive compulsive disorder (17.4%), social anxiety disorder (16.6%), agoraphobia (16.6%), generalised anxiety disorder (15.4%), separation anxiety disorder (9.0%), and panic disorder (1.8%).

Moderator analyses revealed that the method of measurement was associated with higher rates of anxiety in general, and the specific anxiety subtypes generalised anxiety disorder, separation anxiety disorder and, to some extent, social anxiety disorder. Mean age had a significant moderating effect on the prevalence rates of obsessive compulsive disorder and social anxiety disorder, and to a lesser degree on anxiety in general, and generalised anxiety disorder. IQ had a significant effect on anxiety in general, as well as general anxiety disorders, and a lesser effect on obsessive compulsive disorder and separation anxiety disorder. Anxiety in general was more likely to be diagnosed in young people with Asperger’s syndrome or PDD-NOS.

Some anxiety disorders were more strongly associated with one or more autistic spectrum disorder subtype: autistic disorder was associated with higher rates of obsessive compulsive disorder and lower rates of generalised anxiety disorder; Asperger’s syndrome was associated with lower rates of specific phobia, and obsessive compulsive disorder, and; PDD-NOS was associated with lower rates of obsessive-compulsive disorder but higher rates of specific phobia and generalised anxiety disorder.  

Authors' conclusions

‘The results reveal substantial comorbidity for anxiety in children and adolescents with an autistic spectrum disorder: almost 40 percent were estimated to have clinically elevated levels of anxiety or at least one anxiety disorder’. Some significant moderator effects were identified to explain the wide heterogeneity found across the meta-analyses but heterogeneity remained significant across all fixed models.

Implications for policy or practice

None are discussed.

Subject terms:
young people, anxiety, autistic spectrum conditions, children, comorbidity;
Content type:
research review
Link:
Journal home page
ISSN online:
1573-2827
ISSN print:
1096-4037

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