| Fragile X syndrome (FXS) is a genetic disorder recognized as the most common form of inherited intellectual disability (ID). Previous research has also revealed prevalence of co-occurring conditions among individuals with FXS, including anxiety disorders. However, difficulties diagnosing and subsequently treating internalizing disorders, such as anxiety in individuals with FXS is complicated by the failure to fully capture the manifestation of anxiety symptoms observed in individuals with FXS when solely measuring clinical symptoms of anxiety as defined by the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5; American Psychological Association [APA], 2013). Additionally, internalizing emotional and behavioral problems, such as anxiety in individuals with FXS are often masked by the prevalence of observable, externalizing behaviors. Likewise, due to the severity of ID, individuals with FXS are limited in their ability to recognize and verbalize their thoughts and emotions, making it particularly difficult to diagnose and subsequently treat anxiety symptoms. Difficulty in accurate assessment of anxiety symptoms may also be attributed to a significant lack of valid and sensitive measures designed to assess anxiety among individuals with FXS. The purpose of this study was to evaluate symptoms and behaviors indicative of anxiety in youths with FXS. This was done using the Aberrant Behavior Checklist--Community Edition (ABC-C) FXS-specific 6-factor model to assess its relationship with anxiety as measured by the Pediatric Anxiety Rating Scale--Revised (PARS-R) to evaluate the utility of the ABC-C 6-factor model as a clinical screener for anxiety. Additionally, this study sought to determine whether behavioral indicators of anxiety vary with severity of ID. Analyses were conducted used data from 17 parents with at least one child diagnosed with FXS. Parents completed the ABC-C and were interviewed using the PARS-R. Participants with FXS completed the Stanford-Binet Intelligence Scales, Fifth Edition (SB5) to evaluate cognitive abilities. Results revealed the Stereotypy subscale of the ABC-C 6-factor model, as well as the ABC-C total sum score to be useful predictors of anxiety as measured by the PARS-R. IQ group status (mild vs. moderate to severe) and mental age accounted for a significant amount of unique variance in the PARS-R. Overall findings provide further support for the importance of accurate assessment of anxiety in individuals with FXS in order to provide appropriate treatment and improve overall prognosis. Future studies should aim to replicate these results with a larger sample, while also seeking to recruit a greater number of females with FXS in order to account for the small sample of participants in the mild IQ group. |
